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Glossary

Computing has a habit of hiding simple ideas behind scary acronyms. Half the battle in this course is just vocabulary — so here is every new word in one place, in plain language. When a word shows up in class or on this site, it lands here.

A

Term What it means Where you met it
Acceptance test Numbers or facts you fix before changing the code, which say when the change is done. Unit 6 · Change and export
Accessibility Making an interface that people with the widest range of abilities can perceive, understand and use — the ramp next to the stairs, which ends up helping everyone. Unit 1 · Accessibility
Accessibility audit Checking an interface against accessibility rules such as WCAG, by hand and with tools. The inspector visiting the building. Unit 1 · Wireframes and tests
Action What the app does in answer to an event: the chime when someone rings the doorbell. Unit 3 · Events and actions
Adapter The SvelteKit plugin that shapes the build for the place it will run. adapter-static writes a folder of plain files. Unit 8 · Wrap and package
Administrator Whoever installs an app and keeps it running — the person who punches out the pieces before anyone plays. Unit 7 · Where help lives
Aesthetic integrity 1987 Apple principle: a confusing or ugly screen makes the app harder to use. Different things look different, and the app never makes a mess. Unit 1 · Apple HIG
Alt text Alternative text: the written description of an image that a screen reader reads out instead of showing it. Decorative images get an empty one (alt=""). Unit 1 · Accessibility
Apache ECharts A free, open-source JavaScript library that draws a chart from an object describing it. Unit 6 · Charts with ECharts
API The list of requests a server accepts: the restaurant's menu. Unit 3 · Consuming data
AppImage A Linux package that is one file with nothing to install: make it executable and run it. It carries its own libraries, so it is heavy. Unit 8 · Installers and wizard
Apple Desktop Interface Apple's 1987 name for the system its first guidelines book describes: a desktop with windows, icons, menus and a pointer. Unit 1 · Apple HIG
Asset A file your page uses but does not contain, such as an icon or a logo. Unit 2 · Generated code
Augmented reality (AR) Virtual elements added to the real world, live, and glued to their place. Azuma's three conditions: real and virtual combined, interactive in real time, registered with the world. Unit 5 · Gestures, faces and AR
Auto layout Figma arranges a frame's contents for you by direction, gap, padding and alignment — the smart tray that grows when you add a brick. Unit 1 · Figma
Autodocs Storybook feature that generates a component's documentation page from its stories and JSDoc comments — the instruction booklet that comes from the model itself. Unit 4 · Visual tests and docs
axe Deque's open-source accessibility rule engine (2015) and browser extension. It lists each failure with the element and the WCAG criterion. Unit 1 · Wireframes and tests

B

Term What it means Where you met it
Band A horizontal strip of a report with one job, such as the group footer on a receipt. Unit 6 · Report structure
Banner A message bar that stays while a state lasts, such as "You are offline." Unit 1 · Controls and messages
Baseline The approved screenshot a visual test compares against. It is only as good as the person who looked at it before committing it. Unit 4 · Visual tests and docs
Bindable prop A prop shared by parent and child, declared with $bindable, so a change on either side reaches the other. Keep it for controls that are a value. Unit 4 · Methods, snippets and events
Biometric data Personal data from technical processing of a person's body or behaviour that allows or confirms who they are. Used to identify someone, it is a special category under GDPR article 9. Unit 5 · Gestures, faces and AR
Blob A chunk of data the browser treats like a file, so a page can offer it as a download. Unit 6 · Change and export
Bootstrapper A small program that downloads and installs something bigger. The Windows installer uses one to get WebView2 if it is missing. Unit 8 · Wrap and package
Breakpoint A window width at which the layout changes its arrangement, not just its size. It is a width, not a device. Unit 2 · Framer first page
Bundle target A package format Tauri can produce: nsis, msi, deb, rpm, appimage, app or dmg. Unit 8 · Installers and wizard
Bundler The part of Tauri that makes the packages for the system it runs on. Unit 8 · Wrap and package

C

Term What it means Where you met it
Calculated value A column computed from other columns of the same row and never stored: store the words, cook the minutes. Unit 6 · Data and totals
Callback prop A function a parent passes to a child, so the child can announce that something happened. Props down, events up. Unit 3 · Events and actions
Cardinality How many of one thing go with another: one note has zero or more tags. Unit 7 · Admin, data, tutorials
Certificate authority A company that checks who you are and vouches for your public key. Unit 8 · Sign and update
Change request A written request to change something that already works; it usually lands in one layer of the code. Unit 6 · Change and export
Checkbox A box you tick, for any number of independent options. It waits for a Save or Send button, like a paper form. Unit 1 · Controls and messages
Checksum A short fingerprint of a file. If one byte changes, the fingerprint changes. Unit 8 · Sign and update
Clean uninstall An uninstall that leaves nothing the installer put on the system: no program files, menu entries, shortcuts or system settings. User data is a separate decision. Unit 8 · Sign and update
Client-side navigation Moving between pages with no reload: SvelteKit intercepts the click on a link and swaps only the page. Unit 3 · Routing and navigation
Code signing Sealing a program with a certificate so the operating system (SmartScreen, Gatekeeper) can check who made it and that it has not changed. Unit 8 · Sign and update
Collection A set of related Figma variables that share the same modes. Unit 1 · Figma
Command-line interface A way of using a computer by typing memorised commands, one line at a time. Nothing on screen tells you what you can do. Unit 1 · Apple HIG
Commit A photo of your project saved in Git, with a message that says what changed. Unit 3 · Development environment
Compiler A program that turns the code you write into code a machine can run. Svelte is one: it works on your PC, before the browser sees anything. Unit 3 · Development environment
Component A reusable Figma element — the mould. Change the main component and every instance updates. Unit 1 · Figma
Component (Svelte) A reusable piece of interface with its own markup, style and logic in one .svelte file. A LEGO brick you never open to use. Unit 3 · Component syntax
Component inventory A table with one row per component, showing what each has and lacks. Empty cells are your to-do list. Unit 4 · Workshop and revision
Component property A control an instance shows in the right panel (variant, boolean, text, instance swap) to change it without digging into its layers. Unit 1 · Figma
Component set The dashed purple box in Figma that holds all the variants of one component. Unit 1 · Design systems
Conformance level How many WCAG criteria an interface meets: A (minimum), AA (the usual and legal target) or AAA (the highest). The levels stack. Unit 1 · Accessibility
Consistency Things that do the same job look and behave the same, inside your app and compared with apps people already know. Like a newspaper keeping the same layout every day. Unit 1 · Design principles
Context menu The short list that opens when you right-click or long-press something. The tool belt: everything in it is also in the menu bar. Unit 1 · Controls and messages
Context-sensitive help Help that appears on the screen, about the control you are using, at the moment you are using it — the rule printed on the card. Unit 7 · Context help
Continuous integration (CI) A service that runs your build commands on fresh machines when something happens in your repository: the robot that builds. Unit 8 · Sign and update
Contrast The difference in colour, size, shape or weight that makes one element stand out from another. The black ink on white paper of the front page. Unit 1 · Design principles
Contrast ratio How different the brightness of text is from its background, from 1:1 (invisible) to 21:1 (black on white). WCAG AA asks 4.5:1 for normal text and 3:1 for large text. Unit 1 · Accessibility
Crate A Rust package, the Rust equivalent of an npm package. Unit 8 · Wrap and package
Cross-compile Building on one system a program meant for another, such as a Windows installer on Linux. Unit 8 · Installers and wizard
CSS custom property A named CSS value that starts with -- and is read with var(--name). How design tokens live in code. Unit 3 · Component syntax
CSV Text with one row per line and values separated by commas. Everything in it is text until you convert it. Unit 6 · Data and totals
Custom property A CSS value you name yourself and read back with var(), such as --space-4. It is how CSS stores a design token. Unit 2 · Generated code

D

Term What it means Where you met it
Data source The place a report takes its rows from: a JSON file, a CSV file, a database or an API. Unit 6 · Data and totals
Declarative You describe what you want and a library works out how to draw it, with no loops or rectangles of your own. Unit 6 · Charts with ECharts
Default value What a component uses for a prop when the parent passes nothing. It applies to undefined, not to null. Unit 4 · Props and default values
Derived value A value calculated from state that recalculates by itself ($derived): a spreadsheet cell with a formula. You never assign it. Unit 3 · Reactivity
Design system The shared decisions of a product, written once and reused everywhere. Three layers: tokens, components and rules. Unit 1 · Design systems
Design token A shared name for a design value (color-background) that designers and developers use instead of raw values like #FFFFFF. Unit 1 · Figma
Detach Turning an instance into a normal frame: the link to its main component is gone for good. Unit 1 · Figma
Detached signature A signature kept in a separate file next to the package, such as a .asc file. Unit 8 · Sign and update
Dev server A program that serves your app on your own PC while you work and refreshes it when you save. Vite is the one you use. Unit 3 · Development environment
Device toolbar The DevTools mode (Ctrl+Shift+M) that shows a page at an exact width you choose. Unit 3 · Layout with CSS
DevTools The developer tools inside your browser (F12), for reading the code and styles of any page. Unit 2 · Generated code
Dialog A window that blocks the app until you decide. Only for the few actions that cannot be undone. Unit 1 · Controls and messages
Diff The image that marks the pixels that differ between a visual test's baseline and its latest screenshot. Unit 4 · Visual tests and docs
Digital signature A short piece of data computed from a file and a private key. It proves who sealed the file and that it has not changed, not that it is safe: the wax seal on a parcel. Unit 8 · Sign and update
Direct manipulation 1987 Apple principle: you act on the thing itself, on the screen, and watch it react — drag a photo and it moves. Unit 1 · Apple HIG
Docs map A sitemap of your documentation: each card has a reader, a moment, a format and a file. Unit 7 · Where help lives
Docs-as-code Writing documentation with the same tools as code: plain text, Git, reviews, automated tests and issue trackers. Unit 7 · Where help lives
Documentation Everything that explains the app to someone who is not you. Unit 7 · Where help lives
dp Density-independent pixel: Android/Material's size unit, the equivalent of Apple's point. Unit 1 · Apple HIG
Dropdown A closed list that opens on click, for choosing one option out of many (6 or more). Unit 1 · Controls and messages
Dynamic route A folder whose name is a parameter, like notes/[id]: one plan for many houses. Unit 3 · Routing and navigation

E

Term What it means Where you met it
Edge trigger Code that fires on the change from false to true, not while the condition stays true: the referee's single whistle. Unit 5 · Pose detection
Effect A function ($effect) that runs after the page updates, to touch something outside it: the tab title, storage, a timer. Unit 3 · Reactivity
Effectiveness / Efficiency / Satisfaction The three measures of usability: did you reach the goal, at what cost in effort, and how did it feel. Unit 1 · Usability heuristics
Electron A way to put web technology in a desktop window by shipping a whole Chromium inside each app: it carries a browser. Unit 2 · GUI tools
Ellipsis The three dots after a command, as in "Save As...". They mean: I will ask you something before I act. Unit 1 · Controls and messages
Embedded report A report that lives inside the app: reached from its navigation, reading its data, looking like it. Unit 6 · Change and export
EN 301 549 The European accessibility standard for ICT products and services (UNE-EN 301549 in Spain). For web content it includes all WCAG A and AA criteria; the law points to it. Unit 1 · Accessibility
Endpoint A URL that answers with data instead of a page. In SvelteKit, a +server.js file. Unit 3 · Consuming data
Entity One kind of thing an app stores, such as a note or a book. Unit 7 · Admin, data, tutorials
Entity-relationship diagram A drawing of the entities an app stores, their fields and how they connect. Mermaid writes it as erDiagram. Unit 7 · Admin, data, tutorials
Error message What the form says when data breaks a rule. A good one answers which field, what is wrong and how to fix it. Unit 3 · Forms and validation
Event Something that happens, usually something the user does: a click, a key, a submit. Someone pressing the doorbell. Unit 3 · Events and actions
Event object What every handler receives, describing what happened: event.key, event.preventDefault(). Unit 3 · Events and actions
Event-action table A table of a screen's promises, written before the code: where, which event, which action. Unit 3 · Events and actions
Exported method A function a component makes available to its parent with export function, reached through bind:this. An order, not a fact. Unit 4 · Methods, snippets and events
External tool A packaging program that does not belong to Tauri, such as dpkg-deb, makensis or WiX. Unit 8 · Sign and update

F

Term What it means Where you met it
F-pattern How people scan web pages: a sweep across the top, a shorter sweep lower down, then a scan down the left edge (Nielsen Norman Group eye-tracking, 2006). Unit 1 · Design principles
Face detection Finding whether there is a face and where: a box and 6 key points. It does not know whose face it is. Unit 5 · Gestures, faces and AR
Face recognition Working out whose face it is. Not in MediaPipe and not in this course. Unit 5 · Gestures, faces and AR
Fallback page The one HTML page that loads a SvelteKit app and then shows the right route. Unit 8 · Wrap and package
fetch The browser function that sends a request and returns a promise of a response. It does not fail on a 404. Unit 3 · Consuming data
Fidelity How close a sketch is to the finished product. Low fidelity is grey boxes; high fidelity has the design system applied. Unit 1 · Wireframes and tests
Figma The design tool used in this course to draw and prototype screens before coding them. Unit 1 · Figma
File-based routing Every folder inside src/routes is a URL, and the +page.svelte inside it is what that URL shows. Unit 3 · Routing and navigation
Fill container Auto layout resizing: the layer stretches to take all the space its parent gives it. Unit 1 · Figma
Filter The rule that decides which rows enter a report. Unit 6 · Data and totals
Final result The last result of a speech recognition, with isFinal === true: the transcript your code acts on. Unit 5 · Voice commands
Flexbox The CSS feature that lays out items in a row or a column. Figma's auto layout and Framer's stacks are the same idea. Unit 2 · Framer first page
Focus indicator The visible highlight, usually an outline, on the element that keyboard input currently goes to. Never remove it. Unit 1 · Accessibility
Font One cut of a typeface, such as Inter Bold 28. Unit 1 · Design systems
Forgiveness 1987 Apple principle: "Users make mistakes; forgive them." Actions are reversible (Undo, the bin), and warnings are kept for the few that are not. Unit 1 · Apple HIG
fr A CSS Grid unit: one share of the free space left after fixed sizes and gaps. Unit 3 · Layout with CSS
Frame A Figma container layer with its own size, style and constraints — a box with walls. Every screen starts as one. Unit 1 · Figma
Framer A visual editor where the canvas is the website: it publishes and hosts the page, but gives you no files to take away. Unit 2 · Framer first page
Framework A ready-made structure you build your app inside. SvelteKit gives you pages, navigation and data. Unit 3 · Development environment

G

Term What it means Where you met it
Gap In auto layout, the space between the items. Unit 1 · Figma
Gestalt principles Rules for how the brain groups what it sees (proximity, similarity...), first described by Max Wertheimer in 1923. Unit 1 · Design principles
Git The program on your PC that keeps your project's history, one commit at a time. Not the same as GitHub. Unit 3 · Development environment
GitHub A website that stores an online copy of a Git repository. Unit 3 · Development environment
GPG The standard signing tool on Linux. It makes keys, signs files and verifies signatures. Unit 8 · Sign and update
Grand total The total of the whole report, shown once in the report footer. Unit 6 · Report structure
Grid CSS layout in rows and columns at once: a bookcase where every book has a cell. Unit 3 · Layout with CSS
Group A rubber band around some layers: no size of its own, it wraps its contents. Unit 1 · Figma
GUI Graphical user interface: windows, buttons and text fields instead of typed commands. Unit 2 · GUI tools
GUI toolkit The set of ready-made pieces (windows, buttons, text fields) and the code that draws them and delivers clicks to your program. Unit 2 · GUI tools
Guided tour Three or four bubbles in sequence, each pointing at one control, started by the user — the beginners' set-up of the game. Unit 7 · Context help

H

Term What it means Where you met it
Handler The function that connects an event to its action: the wire of the doorbell. Unit 3 · Events and actions
Handoff sheet A table that turns a design into a plan: one row per screen, with its route, file, data, state and events. Unit 3 · Workshop: from Figma to app
Help The documentation the user meets while using the app. Unit 7 · Where help lives
Help ladder The order for adding help: better label, inline help, tooltip, guided tour, link to the manual. Start at the bottom. Unit 7 · Context help
Help-generation system A tool that takes a source and produces help in a format, such as Zensical or Pandoc. Unit 7 · Where help lives
Heuristic A rule of thumb: a short, practical design rule that works most of the time, like a good waiter's habits. Unit 1 · Usability heuristics
Heuristic evaluation Reviewing an interface screen by screen against a set of heuristics to find usability problems; ideally 3–5 independent evaluators. Unit 1 · Usability heuristics
HIG Human Interface Guidelines: Apple's official guide to designing apps for its platforms. First written in 1978, a book with ten principles in 1987, a website with eight principles today. Unit 1 · Apple HIG
HMR (hot module replacement) Vite swaps a saved file into the open page, with no reload. Unit 3 · Development environment
Hold time How long a gesture must be held before it counts, so hands passing by do nothing: the traffic officer holding a signal. Unit 5 · Gestures, faces and AR
Hover state The version of a component shown while the mouse is over it. Touch screens have none, so it can never be the only clue. Unit 2 · Framer project
HTTP method The verb of a request: GET reads, POST creates, PATCH changes part, DELETE removes. Unit 3 · Consuming data
Hug contents Auto layout resizing: the frame shrinks or grows to fit what is inside. Unit 1 · Figma

I

Term What it means Where you met it
Icon set A collection of icons drawn to the same rules: one family, one grid, one stroke. Unit 1 · Design systems
Identifier An app's unique id in reverse-domain form, such as com.iessonferrer.notebox. It names the folder where the user's data lives. Unit 8 · Wrap and package
Inline help One line of text under a field, always visible, for what the user needs to get it right. Unit 7 · Context help
Inline message Text next to a control, about a problem with that field. The quietest voice an app has. Unit 1 · Controls and messages
Installation wizard The series of windows that guides a user through installing a program, with Next and Back buttons: the front door of your app. Unit 8 · Installers and wizard
Instance A linked copy of a component — one brick from the mould. It can override some properties and still update with the main component. Unit 1 · Figma
Interaction principles The seven principles of ISO 9241-110:2020, from suitability for the user's tasks to user engagement. Unit 1 · Usability heuristics
Interim result The provisional words a speech recogniser reports while you are still speaking. Unit 5 · Voice commands
invalidate A SvelteKit function that marks what a URL returned as out of date, so every load that fetched it runs again. Unit 3 · Consuming data
ISO International Organization for Standardization — the body that publishes international standards such as ISO 9241. Unit 1 · Usability heuristics

J

Term What it means Where you met it
Jakob's Law Users spend most of their time on other sites, so they expect yours to work like those (Jakob Nielsen, 2000). Unit 1 · Design principles
JSDoc Types and descriptions written inside JavaScript comments, so that the editor and Storybook can read them. Unit 4 · Props and default values
jsdom A simulated browser page inside Node: fast, but it never draws anything, so it cannot see colours or layout. Unit 4 · Unit tests with Vitest
JSON Text that looks like JavaScript objects and that every language can read. It is text, not an object. Unit 3 · Consuming data

K

Term What it means Where you met it
Keyboard shortcut A key combination that runs a command without the mouse: Cmd+C / Ctrl+C copies. Resources · Figma shortcuts

L

Term What it means Where you met it
Landing page A single page whose job is to present one thing and make you want it. It opens with a hero: the big block with a name, a sentence and a button. Unit 2 · Framer first page
Landmark A numbered point a model finds on the body, hand or face: 33 for a body, 21 for a hand, 478 for a face. Unit 5 · Pose detection
Layout (SvelteKit) A +layout.svelte file: a frame around every page in its folder and below. Unit 3 · Routing and navigation
Lighthouse Google's open-source auditor, built into Chrome DevTools. Its accessibility score of 100 means no automatic failures, never "accessible". Unit 1 · Wireframes and tests
Liquid Glass The translucent material Apple introduced in June 2025 for controls and navigation, which float on their own layer above the content. Unit 1 · Apple HIG
Live region A part of the page, such as role="status", whose changes a screen reader announces by itself. Unit 5 · Natural user interfaces
load A SvelteKit function in +page.js that fetches what a page needs before the page is drawn. Unit 3 · Consuming data
localhost Always means this computer. In class, VS Code forwards it from your PC to your VM, so your dev server answers there only while you are connected and it runs. Unit 3 · Development environment
localStorage A small store of strings in this browser that survives reloads. Not a database: another device or browser finds it empty. Unit 3 · Reactivity
LTS (Long Term Support) The version of a program that gets fixes for years. The one to install. Unit 3 · Development environment

M

Term What it means Where you met it
Modifier key A key that does nothing alone but changes what the next key means: Shift, Ctrl, Alt, Cmd, Option. Resources · Figma shortcuts

Missing a word you heard in class? Tell your teacher — new terms are added as the course moves on.

N

Term What it means Where you met it
Natural user interface (NUI) An interface you operate with what you already do as a person: speaking, moving your hands or body. It is not natural: gestures are invisible, so it needs a vocabulary and feedback. Unit 5 · Natural user interfaces
Nielsen's 10 heuristics The classic usability checklist by Jakob Nielsen (with Rolf Molich 1990, refined 1994): status, real-world match, control, consistency, error prevention... Unit 1 · Usability heuristics
Node.js The program that runs JavaScript outside the browser. Created by Ryan Dahl in 2009. The stove of the kitchen. Unit 3 · Development environment
npm The tool that comes with Node.js and downloads your project's packages into node_modules/. Unit 3 · Development environment
npx Downloads a tool and runs it without installing it. Unit 3 · Development environment
NSIS Nullsoft Scriptable Install System: the tool behind Tauri's -setup.exe Windows installers. Unit 8 · Installers and wizard

O

Term What it means Where you met it
On-device recognition Speech recognition done on your own device, after a language pack download, so neither the audio nor the transcript goes to a third-party service. processLocally = true in Chrome. Unit 5 · Voice commands
Override A change made to one instance only (its text, its colour) while it stays linked to the main component. Unit 1 · Figma

P

Term What it means Where you met it
Package Code written by other people that your project uses, downloaded by npm. Unit 3 · Development environment
Padding In auto layout, the space between a frame's edge and its contents. Unit 1 · Figma
Palette A list of colour jobs, not five colours that look nice together. Unit 1 · Design systems
Pandoc A tool that converts a document from one format to another; with Typst it turns Markdown into a PDF. Unit 7 · Site and PDF
Parameter The value a user or a program gives to a filter, such as School for the folder. Unit 6 · Data and totals
Peer dependency A package your library needs but does not bring: it uses the one in the buyer's project. Unit 4 · Packaging with npm
Perceived stability 1987 Apple principle: the interface keeps familiar landmarks. A command you cannot use turns grey; it does not vanish. Unit 1 · Apple HIG
Persistent data What the app still knows after you close it, wherever it is stored: localStorage, a file, a cookie or a database. Unit 7 · Admin, data, tutorials
Placeholder A ? in an SQL query: the value travels apart from the query, so it can never become part of the command. Unit 6 · Data and totals
Platform interface guidelines The official "highway code" a platform's maker publishes so every app on it looks and behaves in a familiar, predictable way. Unit 1 · Apple HIG
Playwright A tool that drives a real browser from code: go to a URL, press a key, take a screenshot. Unit 4 · Visual tests and docs
Point (pt) Apple's size unit for interfaces: it stays about the same physical size on any screen, whatever its number of pixels. Unit 1 · Apple HIG
Port forwarding Carrying the requests for a port of your PC through a connection to another computer: the delivery rider between your browser and your kitchen. Unit 3 · Development environment
Pose landmarker The model that returns 33 numbered points on a person's body, frame by frame. It knows no poses: a pose is a rule you write. Unit 5 · Pose detection
POUR The four WCAG principles: Perceivable, Operable, Understandable, Robust. Every success criterion hangs from one of them. Unit 1 · Accessibility
Prefix A marker like webkit on a name, from when browsers shipped unfinished features. webkitSpeechRecognition and SpeechRecognition are the same class. Unit 5 · Voice commands
Primary key The field that identifies each record, marked PK in a diagram. Unit 7 · Admin, data, tutorials
Private key The half of a key pair that signs: the stamp. It never leaves your hands. Unit 8 · Sign and update
Promise A value that is not ready yet: the waiter has left but has not come back. await waits for it. Unit 3 · Consuming data
Prop A value a component accepts from outside: the studs of the brick. Props flow down only. Unit 3 · Component syntax
Prototype Screens linked so that someone can click through them. The architect's scale model. Unit 1 · Wireframes and tests
Proximity Elements placed close together are seen as a group, like a photo and its caption. Unit 1 · Design principles
Public key The half of a key pair that checks signatures: a picture of the stamp. Give it to everyone. Unit 8 · Sign and update
Pure function A function whose answer depends only on what you give it, with no side effects: text in, command out, no microphone inside. Unit 5 · Voice commands
PWA Progressive web app: a web app that a browser can install and run like an ordinary app. Unit 2 · GUI tools

R

Term What it means Where you met it
Radio buttons Visible options where choosing one clears the others, for one answer out of a few. Unit 1 · Controls and messages
Reactivity When state changes, everything that depends on it updates by itself, like a spreadsheet. Unit 3 · Reactivity
Reference guide Documentation organised by screen that lists every control, to look up one row at a time — the almanac. Unit 7 · Site and PDF
Registry The shop where packages are published, such as registry.npmjs.org. Unit 4 · Packaging with npm
Regression Something that used to be right and no longer is. Unit 4 · Visual tests and docs
Report Data arranged to answer one question for a reader, like the receipt in your pocket. Unit 6 · Report structure
Repository A project with a Git history. git init creates one. Unit 3 · Development environment
Request What a page asks a server for: your order to the waiter. Unit 3 · Consuming data
Resource The thing a REST API organises itself around, such as notes. Each has its own address. Unit 3 · Consuming data
Resources Extra files declared in bundle > resources so they travel with the packaged app. Unit 8 · Wrap and package
Response What a server answers to a request: the plate, or "sorry, we're out of that". Unit 3 · Consuming data
REST API An API organised around resources, each with an address, and a small set of HTTP methods. Unit 3 · Consuming data
Rest props The props a component did not name, collected with ...rest and usually passed on to an inner element. Unit 4 · Props and default values
Reusable component A piece of interface built once, with a fixed connection, used in many places. It knows nothing about the page it lives in. Unit 4 · Storybook and your first component
Role (colour) The job a colour does in the interface: surface, brand, danger. danger survives a rebrand; red does not. Unit 1 · Design systems
Rubric The table that says how each part of a piece of work is marked. Unit 3 · Review and exam preparation
Rune A word starting with $ that is an instruction to the Svelte compiler: $state, $derived, $effect, $props. Unit 3 · Component syntax
Runner One of the clean machines a CI service uses to run your build. Unit 8 · Sign and update
Rust A compiled programming language. Tauri's small native core is written in it. Unit 8 · Wrap and package

S

Term What it means Where you met it
.svelte.js module A JavaScript file where runes work, loaded once and shared by every page that imports it. Unit 3 · Routing and navigation
Scoped styles CSS in a component that only applies to that component. It cannot leak out, and nobody else's can leak in. Unit 3 · Component syntax
Screen reader Software that reads the interface out loud or to a braille display (VoiceOver, TalkBack, NVDA...). It announces each control's name, role and state. Unit 1 · Accessibility
Secret A value such as a signing key kept in a CI service's vault, never in the repository. Unit 8 · Sign and update
Secure context A page served over https:// or on localhost. Cameras and WebXR only work there. Unit 5 · Natural user interfaces
See-and-point 1987 Apple principle: the options are on the screen and you choose one, instead of remembering a command and typing it. Unit 1 · Apple HIG
Segmented control A row of joined buttons showing a few options, one of them selected. Unit 1 · Controls and messages
Self-signed certificate A certificate you vouch for yourself. It proves the file has not changed, but not who you are. Good for tests only. Unit 8 · Sign and update
Semantic versioning Writing a version as MAJOR.MINOR.PATCH to tell users whether updating is safe: fix, new feature, or breaking change. Unit 4 · Packaging with npm
Server The program that holds the data and answers requests: the restaurant's kitchen. Unit 3 · Consuming data
Severity Nielsen's 0 to 4 rating of a usability problem, from "not a problem" to "catastrophe: fix it before release". Unit 1 · Wireframes and tests
Single source One text from which every format is generated, so a correction reaches all of them. Unit 7 · Where help lives
Skeuomorphism Making digital things imitate real objects (fake leather, paper, wood). Apple dropped it with iOS 7 in 2013. Unit 1 · Apple HIG
Slider A handle on a track, for a number with limits when the exact value matters less. Unit 1 · Controls and messages
Snackbar Material Design's name for a toast. Unit 1 · Controls and messages
Snippet A small piece of code, not a whole program, such as the CSS Figma Dev Mode shows for one layer. Unit 2 · Framer first page
Snippet (Svelte) A named piece of markup you can pass to a component like a value. The child decides where to draw it. Unit 4 · Methods, snippets and events
Spacing scale The short, fixed list of distances a product may use, such as 4, 8, 12, 16, 24, 32. It turns "how much space?" into a pick. Unit 1 · Design systems
Spec card A short description of a report, written before drawing it: question, reader, data, columns, grouping, calculated value, totals and filters. Unit 6 · Report structure
Speech recognition Speech into text: the ear of the Web Speech API. Unit 5 · Voice commands
Speech synthesis Text into speech: the mouth of the Web Speech API. Unit 5 · Voice commands
SQL The language used to ask a database questions, including counting and adding up rows with GROUP BY. Unit 6 · Data and totals
SQLite A database that keeps everything in a single file, first released in 2000. Unit 6 · Data and totals
SSH A secure way of working on a remote computer over the network. VS Code uses it to reach your VM. Unit 3 · Development environment
SSR Server-side rendering: a server sends ready-made HTML. A desktop window has no server, so Tauri apps turn it off. Unit 8 · Wrap and package
SSR (server-side rendering) SvelteKit draws the first version of a page in Node.js before the browser gets it. Node.js cannot see the browser's storage. Unit 3 · Reactivity
Stack Framer's auto layout: a frame that arranges its children by direction, distribution, gap and padding. Unit 2 · Framer first page
Standard An official rulebook agreed by experts and published by a body such as ISO, so things work the same everywhere. Unit 1 · Usability heuristics
Starter project The code you begin an exam from, instead of an empty folder. Unit 3 · Review and exam preparation
State Data that can change and that the screen depends on ($state): a spreadsheet cell you type into. Unit 3 · Reactivity
State vs event A state lasts (the hand is up); an event happens once (the hand went up). The ball is out; the referee whistles. Unit 5 · Pose detection
Status code The number that sums up a response: 2xx it worked, 4xx you asked wrongly, 5xx the server failed. Unit 3 · Consuming data
Stepper − and + buttons around a number, for a value with limits. It always shows the number. Unit 1 · Controls and messages
Story One component in one specific state — a catalogue photo: this brick, in red. Unit 4 · Storybook and your first component
Storybook A separate website for developers where each component is built and viewed alone, in every state — the catalogue. Unit 4 · Storybook and your first component
Style A named, saved set of visual values (colour, text, effect, layout guide). Edit it once and every layer using it updates. Unit 1 · Figma
Subtotal The total of one group, shown in its group footer so that a human can check the sums. Unit 6 · Report structure
Success criterion One testable WCAG rule with a clear yes/no answer, e.g. 1.4.3 Contrast (Minimum). Unit 1 · Accessibility
Svelte A compiler that turns .svelte component files into plain JavaScript. By Rich Harris, 2016. Unit 3 · Development environment
SvelteKit The framework around Svelte: pages, navigation and data. Unit 3 · Development environment
Switch A small lever for one thing on or off, applied at once, like a light switch. Unit 1 · Controls and messages

T

Term What it means Where you met it
Tab bar The bar at the bottom of a phone screen, with 3 to 5 destinations. It takes the place of the menu bar. Unit 1 · Controls and messages
Tarball The compressed .tgz file a package is sealed into — the box itself. Unit 4 · Packaging with npm
Tauri A way to put web technology in a window using the webview the system already has: it borrows a browser. Unit 2 · GUI tools
Template The part of a report that is the same every time, written once: the pre-printed form that the data fills. Unit 6 · Typst PDF reports
Testing Library Tools that put a component on a test page and find things the way a user does, such as by role and name. Unit 4 · Unit tests with Vitest
Text field A box you type into, for answers you cannot list. It accepts every wrong answer, so use it last. Unit 1 · Controls and messages
Think-aloud A test method (Clayton Lewis, IBM, 1982) where the person says what they look at, expect and find surprising. Unit 1 · Wireframes and tests
Toast A small message bar that leaves by itself, for good news with no decision needed. Unit 1 · Controls and messages
Toolbar A strip of buttons for the few most frequent commands. The pegboard on the workshop wall. Unit 1 · Controls and messages
Tooltip A small bubble that opens on hover or focus and closes again, for detail most people do not need. Unit 7 · Context help
Truthy A value JavaScript treats as true in a condition. Any non-empty text is truthy, even "false". Unit 6 · Data and totals
Tutorial A walk through one guided example for a beginner, where every step ends with what you should see. Unit 7 · Admin, data, tutorials
Type scale The short, fixed list of text sizes a product may use, each with a job. Unit 1 · Design systems
Typeface The design of a set of letters, such as Inter. A font is one cut of it. Unit 1 · Design systems
Typst A typesetting system: a markup language plus a compiler that turns text into a PDF. Unit 6 · Typst PDF reports

U

Term What it means Where you met it
UI library Code on top of a toolkit that helps you organise an interface into components. Svelte is one, and it draws nothing by itself. Unit 2 · GUI tools
Unattended installation An installation with no window, no question and no click, also called silent. It is how an administrator deploys to many PCs. Unit 8 · Sign and update
Unit test Code that checks one small piece of the program automatically: arrange, act, assert — the factory's quality-control machine. Unit 4 · Unit tests with Vitest
Unlink Framer's word for Figma's detach: it cuts an instance off from its component, so later changes no longer reach it. Unit 2 · Framer project
Updater signature The seal your own Tauri app checks before installing an update. It is mandatory and cannot be turned off. Unit 8 · Sign and update
Usability How well specific people can reach a goal with an app: effectiveness, efficiency and satisfaction (ISO 9241-11:2018). Unit 1 · Usability heuristics
Usability test A session where a real person tries a real task while you watch, silently. Unit 1 · Wireframes and tests
User flow The path through the screens for one task: the screens, and the actions between them. Unit 1 · Wireframes and tests
User interface (UI) Everything on a screen that lets a person use a machine: buttons, text, icons, menus, gestures. Unit 1 · Design principles
User manual Documentation organised by task, with numbered steps for what the user wants to do — the rules. Unit 7 · Site and PDF

V

Term What it means Where you met it
Validation Checking that data meets the rules before using it. Passport control at the desk, not on landing. Unit 3 · Forms and validation
Variable A named Figma value (colour, number, string, boolean) that can take a different value per mode. Unit 1 · Figma
Variant One version of a component (primary, disabled, small...) grouped with the others in the same component. Unit 1 · Figma
Virtual environment A private folder of Python packages for one project. Unit 7 · Site and PDF
Virtual machine (VM) A computer of your own in a data centre, that you reach over the network: your kitchen, in another building. Unit 3 · Development environment
Visual editor A tool where you build an interface by placing pieces on a canvas instead of typing it. Some also generate the code. Unit 2 · Framer first page
Visual hierarchy The order in which the eye moves through a screen, set by size, weight, colour, position and space. The front page's giant headline. Unit 1 · Design principles
Visual regression test A test that screenshots a component in a real browser and compares it pixel by pixel with an approved screenshot. Unit 4 · Visual tests and docs
Vite The dev server and build tool. By Evan You, 2020; French for "quick". The kitchen line. Unit 3 · Development environment
Vitest The test runner: finds *.test.js files, runs them and reports green or red. Unit 4 · Unit tests with Vitest
Voice vocabulary The table of everything an app understands: what the user says, what the app does and what it answers. Unit 5 · Voice commands

W

Term What it means Where you met it
WCAG Web Content Accessibility Guidelines — the W3C's international rules for accessible digital content; version 2.2 was published in October 2023. Unit 1 · Accessibility
Web Speech API The part of the browser that handles voice, in two halves: recognition and synthesis. Nothing to install. Unit 5 · Voice commands
WebAssembly A compact format that lets the browser run fast code on the processor. MediaPipe's runtime uses it. Unit 5 · Natural user interfaces
Webview A browser engine without the browser around it: no address bar, no tabs, just the part that draws HTML inside an app's window. Unit 2 · GUI tools
WebView A browser engine without the browser: it draws HTML and CSS and runs JavaScript. WebView2 on Windows, WKWebView on macOS, WebKitGTK on Linux. Unit 8 · Wrap and package
WebXR Device API The web standard for AR and VR sessions. immersive-ar needs AR hardware, such as an Android phone with ARCore or a Meta Quest. Unit 5 · Gestures, faces and AR
Wireframe A sketch of one screen: grey boxes and real words, with no styling. The architect's floor plan. Unit 1 · Wireframes and tests
WiX The tool behind Tauri's .msi Windows installers. It only runs on Windows. Unit 8 · Installers and wizard
WYSIWYG "What you see is what you get" (say wizzy-wig): the screen shows the document as it will be printed. Unit 1 · Apple HIG

Glossary

Computing has a habit of hiding simple ideas behind scary acronyms. Half the battle in this course is just vocabulary — so here is every new word in one place, in plain language. When a word shows up in class or on this site, it lands here.

Z

Term What it means Where you met it
Zensical The tool that builds this site: a folder of Markdown files goes in, a documentation website comes out. Unit 7 · Site and PDF