Node.js

However, when we say that Node is built on the V8 engine, we don’t mean that Node programs are executed in a browser. They aren’t. Rather, the creator of Node (Ryan Dahl) took the V8 engine and enhanced it with various features, such as a file system API, an HTTP library, and a number of operating system–related utility methods. -James Hibbard

js:

console.log("Hello, World!"); in app.js

node:

node hello.js in node.js

Result: “Hello, World!”

To my understanding: node.js is another file you can create and put into your website files as a means of requesting callbacks and calling on functions through the use of servers.