"Half of feeling confident as a developer is simply knowing what the words mean. Here are the essentials in plain English."
Learning Objectives
By the end of this module, you will be able to:
- Recognize the most common web development terms
- Explain each in simple language
- Read docs and tutorials with more confidence
The Essential Terms
Bookmark this page and return whenever a word trips you up. Every field has its own vocabulary, and web development is no exception — but none of these ideas are as complicated as their names suggest. You don't need to memorise the list; simply reading through it once builds a mental map, and looking a term up the moment you meet it in a tutorial is how the words gradually become second nature. The definitions below are deliberately plain-language, trading a little precision for a picture you can actually hold in your head.
| Term | Plain-language meaning |
|---|---|
| HTML | The language for a page's structure and content. |
| CSS | The language for styling — colors, layout, fonts. |
| JavaScript | The language that makes pages interactive. |
| Element / tag | A building block of HTML, like <p> or <button>. |
| Attribute | Extra info on an element, like href or alt. |
| Semantic HTML | Tags that describe meaning (<nav>, <main>), not just looks. |
| Box model | Every element as content + padding + border + margin. |
| Flexbox | CSS tool for laying out items in a row or column. |
| Grid | CSS tool for laying out items in rows and columns. |
| Responsive design | Layouts that adapt to phones, tablets, and desktops. |
| Media query | CSS that applies only at certain screen sizes. |
| Variable | A named container for a value (let / const). |
| Function | A reusable block of code that does a task. |
| Method | A function attached to a value, like .toUpperCase(). |
| Condition | Code that runs only when something is true (if). |
| Array | An ordered list of values, counted from 0. |
| Object | A group of named values (keys and values). |
| DOM | The browser's live model of the page that JS can change. |
| Closure | A function that remembers the variables around it. |
| Event / event listener | A user action (click, keypress) and the code that reacts. |
| Client / server | The browser that asks (client) and the computer that answers (server). |
| HTTP | The rules browsers and servers use to talk (GET, POST…). |
| URL | A web address (protocol + domain + path). |
| API | A way for your code to request data from a service. |
| JSON | A lightweight text format for sending data on the web. |
| fetch | The JavaScript function that requests data over the network. |
| Async | Work that happens without freezing the page (await, timers). |
| Local storage | A place to save small data in the browser between visits. |
| Service worker | A background script enabling offline use and caching. |
| Canvas | An HTML element you draw on with JavaScript. |
| Game loop | Update-then-draw, repeated many times per second. |
| Routing | Choosing which content to show for which URL. |
| State | The app's current data (login, cart, balance…). |
| Accessibility (a11y) | Designing so everyone, including disabled users, can use your site. |
| Git / GitHub | Version control for code / the site that hosts it online. |
Explain like I'm new: Jargon isn't there to gatekeep — it's shorthand. Once "the DOM" means "the live page JavaScript can change," a whole sentence of documentation collapses into three letters. Learning the words is really just learning to read and communicate faster.
Try this: Cover the right-hand column and read each term aloud, giving the meaning from memory. The handful you stumble on are precisely the modules worth revisiting — a glossary doubles neatly as a quick self-test.
Key idea: Notice the layers: HTML structures, CSS styles (Flexbox/Grid/responsive), JavaScript (via the DOM, events, and closures) adds behavior, fetch/JSON/APIs bring in data, routing/state organize an app, and accessibility + Git keep it usable and safe.
Key Takeaway: These ~35 terms cover the whole course — the three languages, HTML/CSS building blocks and layout, JavaScript core concepts, the DOM/events/closures, the client/server web, APIs and JSON, async and performance, canvas, routing, state, plus accessibility and version control. Keep this page as your quick reference.
Further Learning
Terms adapted from Microsoft's Web Dev for Beginners (MIT License).