Glossary

129 terms from building websites and apps with AI, explained without jargon. Each links to the exercises that practise it.

A B C D E F H I K L M N O P R S T V W

A

A record: A DNS entry that points a domain at a numeric internet address.
Accessibility: Making a site usable by everyone, including people who use screen readers, keyboards or zoom.
Adapter: A small piece of code that translates between your app and a service. Your Store is an adapter for data.
Alt text: A short description of an image. Screen readers read it aloud, and it shows if the image fails to load.
Analytics: Counting visits and actions on your site, such as how many people clicked 'Book'.
Anchor link: A link that jumps to a spot on the same page, such as the contact section.
Anchor links: Links like #contact jump within the page. They also give you a simple navigation without scripts.
API: A way for one program to ask another for data or actions, like a waiter taking orders between you and the kitchen.
Audience framing: State who reads the page and what they want to do. The model picks vocabulary and emphasis from that.
Audit: An automatic review of accessibility, search, speed, safety and content, scored out of 100. A quick check, not a replacement for Lighthouse.
Authentication: Checking who someone is, usually by signing in. Let a trusted provider handle it rather than storing passwords yourself.

B

Browser runtime: The browser runs your HTML, CSS and JavaScript on every phone and computer, so a first version needs no install.
Bug report: A short note with what goes wrong, what you expected and how to see it again. The AI, like a person, fixes what it can see clearly.

C

Cache: A saved copy kept to load faster. After a change you may see the old copy for a short while.
Call to action: The button or link that tells visitors the next step, such as 'Book a walk'.
CDN: A network that keeps copies of your site in many places, so it loads quickly near every visitor.
Checks: Pass-or-fail tests for this module. All must pass before you can accept a version.
Clicks: How many times people chose your link in the search results.
CNAME: A DNS entry that points one name at another name, often used for www.
Config: One block holding names, keys and addresses, so moving to a new platform means editing one place.
Constraints: Hard limits (word count, number of sections, two colors) make versions comparable, so you can see what a change did.
Content: Whether the words do their job: enough real text, easy to read, a clear next step and no filler.
Context: Everything the AI can see in a chat. A long chat of failed attempts can mislead it more than it helps.
Contrast: How different the text color is from the background. Low contrast is hard to read, especially in sunlight or with weaker eyesight.
Cookie notice: A message asking visitors before you store tracking data in their browser. Whether you need one depends on the tool and where visitors live.
Cross-site scripting: An attack where typed text is run as code. Showing text with textContent, never innerHTML, prevents it.
CSS: The rules that control how a page looks: colors, fonts, spacing and layout.
CSS custom properties: Named values, such as --accent: #2f6f5e, set once and reused. Change one line and the whole page updates.

D

Database: An organized place to store information that changes, such as orders, bookings or members.
Defensive input: Treating everything that comes in, typed or imported, as possibly wrong and checking it before use.
Deployment: Putting a new version of your site online.
Design tokens: A small set of named values (two colors, one font, a spacing unit) used everywhere keeps a page consistent.
Diff thinking: Treat each version as a small diff from the last. Small diffs are easy to review and to undo.
DNS: The internet's address book. It turns a domain name into the location of the computer that hosts the site.
Domain: Your site's address, such as greenstreetbakery.com. You rent it yearly from a registrar.

E

Empty state: What a screen shows when there is nothing yet. It should say what the screen is for and how to start.
Error state: What the app shows when something fails. It names the problem and what to do, and never loses the person's data.
Events: A click, key press or form submit that the page can react to. Code listens for events and runs when one happens.
External resource: A file loaded from another website, such as a font or image. Each one adds a wait and a dependency.

F

Fact sourcing: Keep a list of facts you supplied. Anything on the page that is not on the list needs a source or removal.
Favicon: The small icon in the browser tab and in bookmarks. Without one, a site looks unfinished.
Focus: The control that currently receives key presses. Keep it visible and move it on purpose after an action.
Form backend: A service that receives what visitors type into a form and emails or stores it, so a static site needs no server.
Fresh start: A new chat that begins with a short, accurate summary instead of the whole history.

H

h1: The single biggest heading on a page. It says what the whole page is about.
h2: A section heading, one level below the main heading.
Hallucination: When an AI states something that sounds right but is made up, such as opening hours nobody gave it.
Heading hierarchy: One h1, then h2 for sections, h3 inside them. Skipping levels confuses screen readers and outlines.
Heading order: Headings go from h1 (the page title) to h2 (sections) to h3 (sub-sections) without skipping a level, like a table of contents.
Hex code: A color written as # and six characters, such as #1f2933. It gives an exact color, unlike a name like 'blue'.
Hosted checkout: A payment page run by the payment company. Card details never touch your site, which is safer and simpler.
Hosting: A service that keeps your site's files on computers that are always online, so anyone can visit.
HTML: The text that describes what is on a web page: headings, paragraphs, links and images. Browsers read it to show the page.
HTTPS: The secure version of a web address, shown with a padlock. It keeps what visitors send private.

I

Impressions: How many times your page appeared in search results, whether or not anyone clicked.
Impressions vs clicks: Many impressions with few clicks usually means a weak title or description, not a weak page.
Indexing: When a search engine has read and stored your page so it can appear in results.
Information architecture: Decide the sections and their order before styling. Structure is what visitors and search engines read first.
Inline CSS: Styles written inside the page itself instead of in a separate file. Fine for small pages.
Input validation: Checking what people type before using it: how long, what shape, whether it is empty.
Iteration: Improving in small rounds: try, look, change one thing, try again.

K

Keyboard access: Every control can be reached and used with Tab, Enter and Space, without a mouse.

L

Labels: Text tied to a field with the for attribute, so the field has a name for everyone and a bigger tap target.
Landmarks: Labels for the big areas of a page, such as header, main and footer. Screen reader users use them to jump around, like chapters in a book.
Lighthouse: Free tools from Google that test a live page for speed, accessibility and SEO.
Link text: The words a visitor clicks. 'See our cake prices' tells them where they are going; 'click here' does not.
Live region: An element whose changes are read aloud by screen readers, such as a status or alert message.

M

mailto link: A link that opens the visitor's email app with your address filled in.
Major change: A version that changed something important: checks fixed or broken, the audit score moved 5 or more points, or the page structure changed.
Media query: A CSS rule that only applies on certain screen sizes, for example 'one column below 600px wide'.
Merchant of record: A company that sells on your behalf and handles sales tax or VAT, often used for digital products.
Meta description: A one- or two-sentence summary that search engines often show under your link. Think of it as your pitch in the results.
Meta tags: Hidden lines at the top of a page that describe it to browsers and search engines, such as the title and description.
Mixed content: An HTTPS page that loads something over plain HTTP. Browsers may block it or warn visitors.

N

Navigation state: Remembering in the state object which screen is showing and which item is open.
noopener: A setting on links that open a new tab, so the other site cannot control your page.

O

Open Graph: Tags that control the title, text and image shown when someone shares your link on social apps or in chats.

P

Page title: The name of the page shown in the browser tab and as the blue link in search results.
Payment processor: A company that takes card payments for you and sends the money to your account.
Performance: How quickly a page loads and responds, especially on a slow phone connection.
Permissions: Rules about who may do what. They must be checked on a server, because anything in the browser can be edited by the visitor.
Placeholder: Filler text that stands in for real content, such as 'Lorem ipsum' or 'Your text here'. Never publish it.
Placeholder discipline: Mark unknowns as clearly labeled placeholders you must fill in, not plausible-looking guesses.
Platform-neutral: Code that does not depend on one vendor's tools, so you can move it later.
Portable data: Data in a plain format such as JSON that any platform can read, so it can move with the person.
Prompt: What you type to tell the AI what to build.
Prompt specificity: A prompt that names the audience, content and constraints leaves the model fewer ways to guess wrong.

R

Readability: How easy the text is to read. Shorter sentences and everyday words score better.
Registrar: A company that sells and renews domain names.
Regression: Something that used to work and now does not.
Render function: One function that draws the screen from the state. Change the state, call it again, and the screen is right.
Repository: A folder of project files that keeps every saved version, so you can see changes and undo mistakes.
Reproduce: To make the bug happen again on purpose, with the same steps. A bug you can reproduce is half fixed.
Responsive: A layout that rearranges itself to fit any screen, from a phone to a wide monitor.
Rotating a key: Replacing a key with a new one and cancelling the old one. Do this whenever a key may have been seen by someone else.

S

Sandbox: A walled-off area. Your preview runs in one, so a page cannot run code or reach anything else.
Scoped change: A request that names one change and says what must stay the same, so the AI has less room to break other things.
Scoped edits: Name what to change and what to keep. Models rewrite more than asked unless you fence the change.
Screen reader: Software that reads a page aloud for people who cannot see the screen.
Screens: One view of the app at a time, such as list, add or detail. They are sections on the web and views on a phone.
Search Console: A free Google tool that shows which searches show your site, how often people click, and any problems found.
Secrets: Keys and passwords that grant access. They belong on a server or in a secrets manager, never in a page or a public code repository.
Section: A block of a page about one topic, usually with its own heading.
Security: Whether the page could be misused, for example a form that sends data somewhere unexpected or a link that hands control to another site.
Semantic HTML: Tags such as header, section and h1 describe meaning, not just looks. Search engines and screen readers depend on them.
SEO: Making pages easy for search engines to understand, so the right people can find them.
Server-side checks: Checks done on a server. Limits in the page help honest visitors, but only a server can stop a dishonest one.
Sitemap: A file listing the pages of your site so search engines can find them all.
Spam bots: Programs that scan pages for email addresses to send junk mail to.
Specific copy: Facts beat adjectives: hours, prices, location, what is included. Supply them; do not let the model invent them.
SQL: The common language for asking a database questions, such as 'show all orders from today'.
State: The data an app is holding right now, such as its list of items and which screen is showing.
Static site: A site made only of files that are sent as they are. Nothing is calculated on a server, so it is fast, cheap and simple to host.
Store: A small piece of code that is the only place data is read or written. Screens ask it; they never touch storage.
Structured data: Extra labels that tell search engines exactly what something is, such as a product, an event or a local business.
Subdomain: An address that sits under another domain, such as yourname.somehost.app. Free hosts give you one.

T

Table: In a database, a list of the same kind of thing, like a spreadsheet tab of orders.
Tap target: Anything a finger presses on a phone. It should be big enough, about 44 pixels, to hit without zooming.
Test mode: A practice mode where payments are pretend, so you can try everything without real money.
TLS certificate: The digital ID that makes HTTPS work. Most hosts create and renew it for you.
Tone control: Describe tone with two or three adjectives plus one example sentence. Adjectives alone are interpreted loosely.
Touch targets: Buttons big enough for a thumb. About 44 pixels is a common minimum.
TXT record: A DNS entry that holds text, often used to prove you own a domain.
Type scale: Pick a base size and a ratio for headings. Consistent steps look professional without effort.

V

Validation: Checking what was typed before using it, and explaining a problem in words the person can act on.
Value proposition: One sentence that says who it is for and what they get. Put it in the h1 or the line right under it.
Viewport: The visible area of the screen. One tag tells phones to use their real width so the page is not shown tiny and zoomed out.

W

Webhook: A message one service sends to another automatically when something happens, such as 'payment received'.
Wrapper: A native shell that shows your web app inside a phone or desktop app and gives it access to device features.