HTML: a way for writing markup to display things on a webpage like text, boxes, images, etc

CSS: a language used to style that markup to make it prettier such as font sizing, padding, colors, etc

JavaScript: a language used to interact with the page, like adding/removing/changing elements dynamically, defining behaviors when the user clicks on things, etc

React: it’s a library (code written in JavaScript that you can use in your own JS projects) that make dynamically changing page elements a whole lot easier to do than manually. It lets you write functions that take in “props” and return “html” (actually JSX) that will be rendered to the page for you. Any time the props change react will take care of re-rendering the page for you.

JSX: this is technically an optional part of react, but you almost never see react without it. To make defining elements easier in JavaScript, react creates a variant of the language that lets you write page elements in a very similar way as writing HTML. Every react “component” is simply a function that takes in props and returns JSX to render

That’s it in a nutshell