Node.JS callbacks - question 1: I have 2 files (1) decon_t2_calledFile.js and (2) decon_t2_callingFile.js. My aim is to take the string output of file 1 (decon_t2_calledFile.js) and access through file 2 (decon_t2_callingFile.js))

decon_t2_calledFile.js

module.exports = function(callback){
	
	function () {
		// Contents of this anonymous function will serve as output 
		// from this file
		console.log('** Output from decon_t2_calledFile.js ** ');	
	}
};

decon_t2_callingFile.js

var someInput = require('./decon_t2_calledFile.js');

// display contents of  'decon_t2_calliedFile.js'
someInput(function(callback){
	callback();
}); // should display ('** Output from decon_t2_calledFile.js **

You could say it's the result of the callback function. That would be appropriate.

A callback is generally defined as a function that runs after something else runs.

What does that statement mean in the context of :

//decon_t2_callingFile.js
var someFunction = require('./decon_t2_calledFile.js');

// display contents of  'decon_t2_calliedFile.js'
someFunction(function(myString){
    console.log(myString);
});

What else is happening here? This will help me to identify it in future, as my previous definition of merely placing a function inside another function is wrong.
Thanks Andrew.

That "something else" would be anything asynchronous like fetching a webpage or making a database request. If you have synchronous code, callbacks are really adding any value because a simple return statement could get the job done just fine.