Every term,
in plain English.

Designing and building websites so that everyone can use them, including people who rely on screen readers, keyboards or other assistive tools.

A sequence of steps in MongoDB that filters, groups and reshapes documents in order, a bit like an assembly line for data.

A short written description of an image that screen readers announce and that shows when the image cannot load.

A set of rules that lets one program ask another program for data or actions, such as a website asking a server for a list of courses.

The actual value passed when calling the function.

A set of HTML attributes that add extra meaning for assistive technology when no native element does the job.

An ordered list of values, such as a shopping list, where each item has a numbered position.

A way to write code that waits for slow work such as a network request without blocking everything else.

Extra information written inside an opening tag, such as href on a link or src on an image.

Proving who a user is, usually with a username and password, before allowing them in.

The simplest input in a recursive function where it stops calling itself and starts returning answers.

A shorthand for describing how much slower an algorithm gets as the amount of data it works on grows.

In Rust, temporarily letting one part of the code use a value while the owner keeps control of it.

The idea that every element is a box made of content, padding, border and margin, each adding space around the next.

A separate line of work in Git where you can make changes without touching the main version.

A function passed to another function.

The rules the browser follows to decide which CSS applies when several rules could match the same element.

In Go, a pipe through which goroutines send values to each other safely at the same time.

A blueprint that describes what data and actions a certain kind of object will have.

A function that remembers the variables from the place where it was created, even after that code has finished.

A group of documents in MongoDB, similar to a table of rows in a relational database.

An invisible shape in Unity that lets an object bump into or overlap other objects in the game world.

A saved snapshot of your project in Git, with a message describing what changed.

A program that turns source code written in a language like C into machine code a computer can run.

A reusable, self-contained piece of a React interface that combines markup, logic and styling.

A concise expression that builds a collection.

A lightweight package that bundles an app with everything it needs to run, so it behaves the same everywhere.

A way in React to share values such as the logged-in user across many components without passing them down by hand.

The amount of text an AI model can keep in view at once when reading and writing its answer.

An attack that tricks a logged-in user's browser into making a request they never meant to make.

A temporary named query you define at the top of a SQL statement to make a complex query easier to read.

A named value in CSS, often written as --brand-color, that you define once and reuse anywhere.

A category of value, such as a number, string or boolean, that tells the program what it can do with the value.

A decorator that generates common methods.

A parameter value used when the argument is omitted.

An outside library or package your project relies on, such as a framework or a small helper.

A shortcut for pulling values out of an array or object and giving them their own names.

A collection that stores values under unique keys, so you can look something up by its key instead of its position.

The phonebook of the web that turns a readable domain name into the numeric address of a server.

A text file of instructions Docker follows to build a custom image step by step.

A single record in MongoDB, stored as a flexible, JSON-like set of fields and values.

The tree of elements a browser builds from your HTML, which your JavaScript can read and change.

An opening tag, its content and its closing tag together, such as a whole paragraph.

A type that can only be one of a fixed set of named values, such as a day of the week.

A value stored outside your code, often a secret or a setting, that the program reads at runtime.

A signal that something happened, such as a click or a keypress, that your code can listen for.

The mechanism in JavaScript that keeps the program responsive by handling one task at a time and queueing the rest.

An object that signals something went wrong, which your code can catch and handle instead of crashing.

A popular Node.js framework that makes building web servers and routes far less code.

A browser function that asks a server for data over the network and hands back the response.

A CSS layout mode for arranging items in a row or column and distributing space between them.

The state of an element that is currently ready to receive keyboard input, shown as an outline on buttons and links.

A column that links rows in one table to the primary key of another table, connecting related data.

A named block of code you can call over and over, optionally passing in values and getting one back.

A function in Python that produces values one at a time with yield instead of building the whole list up front.

A way to write code that works with any type, so one function can handle strings, numbers or your own types.

Read a key with a fallback instead of raising KeyError.

A version control system that records every change to your files so you can revisit or undo them.

A lightweight thread in Go that runs a function at the same time as others, started with the go keyword.

A data structure of nodes connected by edges, used to model networks such as roads or friendships.

A two-dimensional CSS layout system for placing items into rows and columns.

A SQL clause that groups rows that share a value so you can count or total each group.

When an AI model confidently states something that sounds right but is not actually true.

A structure that stores key-value pairs and can look up a value in near-constant time.

A function that takes or returns a function.

A React function such as useState that lets a component remember values or react to changes.

The markup language that describes the structure and meaning of content on a web page.

The set of rules a browser and a server use to exchange requests for pages and responses with the files.

A read-only template in Docker from which containers are created, like a recipe for an environment.

A database structure that speeds up lookups on a column, much like a book's index speeds up finding a topic.

A class taking on the fields and methods of another class so shared behaviour is written once.

One object created from a class.

A contract that lists the shape or methods a type must provide, without saying how they are built.

A SQL operation that combines rows from two tables using a column they share.

A lightweight text format for storing and exchanging data, built from objects, arrays and simple values.

A syntax that lets you write HTML-like tags directly inside JavaScript to describe React components.

A testing framework for Java that lets you write and run automated checks on your code.

The unique identifier in a dictionary.

A semantic region of a page, such as a header, main or nav, that helps users jump around.

One step in a Docker image, where each instruction in the Dockerfile adds a cached slice on top of the last.

When visible content suddenly moves because something, usually an image, changed size after loading.

Delaying the download of content, such as an image, until it is actually near the screen.

A compact Python expression that builds a new list from another collection in one line.

A stable unique value on each item in a React list that helps React track which item is which.

A large language model, an AI system trained on huge amounts of text to predict and generate language.

A block of code that repeats while a condition is true or for each item in a collection.

A CSS rule that applies styles only when the screen or device meets certain conditions, such as a narrow width.

Storing the result of an expensive call so the same question does not get computed again.

When two branches changed the same lines, and Git cannot decide which version to keep without your help.

A function defined on a class.

Requiring more than one proof of identity, such as a password plus a code from your phone, to sign in.

Code that runs between the request arriving and the route handling it, often to log or check access.

A file or package of code that can be imported and reused in other parts of a program.

A C++ technique for handing a resource from one object to another without copying it.

A value that can be changed in place, like a list.

Organizing a database into related tables to avoid repeating the same data in many places.

A database value that means no value, or unknown, which behaves differently from zero or an empty string.

The Rust rule that each value has one owner responsible for cleaning it up, preventing memory bugs.

A bundle of code, such as a Python module folder, that can be installed and imported by name.

A named input in the function definition.

A scam that pretends to be a trusted message or site to trick you into giving away your password or details.

A variable in C that stores a memory address, letting you refer to where data lives.

Treating objects of different types through one shared interface so the same code works for each.

A reusable Unity template of a GameObject and its components that you can place many times.

A column whose value uniquely identifies each row in a table, such as an id.

A JavaScript object that represents work that will finish later, either with a result or an error.

The inputs a React component receives from its parent, passed down like arguments to a function.

A request to merge one branch into another, usually with a review before the change is accepted.

Same input, same output, no side effects.

A Python testing framework that finds and runs test functions and reports which pass or fail.

A first-in, first-out structure, like a line at a ticket counter, where the oldest item is handled first.

A C++ idiom where acquiring a resource, like memory, is tied to an object's lifetime so it is freed automatically.

A function that solves a problem by calling itself on a smaller version of the same problem.

A pattern language for matching text, such as finding every email address in a document.

An online store of Docker images, such as Docker Hub, where you can push and pull images.

A copy of your Git repository hosted elsewhere, such as on GitHub, that you push and pull from.

Making a layout adapt smoothly to different screen sizes instead of designing for one fixed width.

A Unity component that gives an object realistic physics, such as gravity and forces.

A mapping between a URL path, such as /courses, and the code that responds to requests for it.

The structure of a database: which tables, columns and types it contains and how they relate.

The part of a program where a variable or function is visible and can be used.

A pattern in CSS that picks which elements a rule applies to, such as h1 or .card.

Using elements that describe their meaning, like header and nav, instead of only generic divs.

A flexible, growable list in Go that refers to a portion of an underlying array.

A C++ object that wraps a raw pointer and manages freeing the memory automatically.

How CSS decides which rule wins when two selectors target the same element, based on how specific each is.

The ... syntax that expands an array or object's items into individual values or properties.

An attack that slips malicious code into a database query through unvalidated user input.

A last-in, first-out structure, like a stack of plates, where the most recently added item is removed first.

Data a React component remembers and that can change over time, driving what the interface shows.

The standard library of C++, full of ready-made containers and algorithms like vector and sort.

A value type that groups related data fields into one unit, such as a point with x and y.

A query nested inside another query, whose result is used by the outer query.

The markup itself, such as <p> or </p>.

A C++ feature that lets you write a function or class once and have it work with many types.

A written plan of who could attack a system, how, and what you do to stop or reduce the damage.

The encryption layer that keeps data private and tamper-proof while it travels between a browser and a server.

A short-lived proof that a user has signed in, sent with requests so the server knows who they are.

In Rust, a collection of methods a type can implement, similar to an interface in other languages.

A group of database changes that all succeed or all fail together, never half-applied.

A Unity collider that detects overlap and fires events without blocking an object's movement.

A fixed, ordered collection of values, often of mixed types, that cannot be changed after creation.

When the compiler figures out a variable's type from the value assigned to it, so you do not write it.

A TypeScript type that accepts one of several allowed types, such as string or number.

An automated check that a single function or piece of code behaves correctly on its own.

Assign several values in one statement.

The address of a page or resource, made up of a scheme, domain and path.

A React hook for managing more complex state through a reducer function and actions.

A named container that holds a value your program can read and change.

An isolated folder for one Python project's packages so projects do not clash with each other.

Storage in Docker that lives outside a container, so its data survives when the container is replaced.

A SQL clause that filters rows so only those matching a condition are returned.

A SQL function that calculates over a set of rows related to the current one, such as a running total.

An attack that injects a script into a page shown to other users, letting the attacker run code in their browser.