The ability of a system to accept input intended for an earlier version of itself.

"Ensuring backwards compatibility allows users to upgrade software without losing access to their existing data or functionality."

Version 6 of the ECMA Script programming language and adds many more features intended to make large-scale software development easier.

"ES6 introduced new features like arrow functions, classes, and template literals to JavaScript."

The numerical position of an element within an array, usually starting from 0.

"To access the first element of an array, you would use the array index 0."

An interactive programming environment that takes single user inputs, executes them, and returns the result to the user.

"Python and Node.js have REPL environments that allow developers to test code snippets quickly."

A software emulation of a physical computer that runs an operating system and applications just like a physical computer.

"Virtual machines allow for the running of multiple operating systems on a single physical machine, isolating them from each other."