# Words you'll see

Plain-English meanings for the words AI apps use as if you already know them. You don't need these to start, just when something sounds scary.

- **HTML**: the content and structure of a page. The words, the buttons, the boxes.
- **CSS**: how it looks. Colours, sizes, spacing, fonts.
- **JavaScript (JS)**: what makes it do things when you click, type, or wait.
- **Frontend**: the part people see and touch in their browser.
- **Backend / server**: a computer somewhere else that stores things or does work for everyone. A lot of first apps don't need one.
- **Database**: where information is stored online so it's the same on every device, or visible to other people.
- **localStorage**: a small drawer in someone's own browser where your app can keep their stuff. Private to them and that device.
- **API**: a way for your app to ask another service for something (the weather, a book cover, an AI answer).
- **API key**: a password for an API. Never paste it into code you share or publish.
- **Framework** (React, Next.js, Vue...): a toolkit for bigger apps. Useful later; not needed for version one.
- **Console**: a hidden panel in the browser that shows errors. Right-click, Inspect, Console.
- **Bug**: anything that doesn't do what you meant.
- **Deploy / ship**: put it online so it has a link.
- **Hosting**: the service that keeps it online (Vercel, Netlify, GitHub Pages...).
- **Repo (repository)**: a project folder that remembers every version, usually on GitHub.
- **Commit**: a saved snapshot of your project in a repo, with a note saying what changed.
- **Responsive**: it works on phones and big screens, not just the one you built it on.
- **Refactor**: tidy the code without changing what the app does. If the AI suggests it mid-build, it's fine to say "not yet".