Node.js is Server-side scripting which is used to build scalable programs. It is a web application framework built on Google Chrome’s JavaScript Engine. It runs within the Node.js runtime on Mac OS, Windows, and Linux with no changes. This runtime facilitates you to execute a JavaScript code on any machine outside a browser.

For a Node.js interview question, a correct answer would typically describe Node.js as follows:

“Node.js is a runtime environment that allows developers to run JavaScript code on the server side. It is built on the V8 JavaScript engine, which is the same engine that powers Google Chrome. Node.js uses an event-driven, non-blocking I/O model, making it lightweight and efficient for building scalable network applications. It provides a rich set of libraries and frameworks that simplify the development of web servers, APIs, and other backend systems. Node.js is particularly well-suited for building real-time applications, such as chat applications, online gaming platforms, and streaming services.”