newbie approach: what is a javascript callback function?

Question

Is just a function that executes after one other function that calls it, finishes?

Please I know (almost) nothing about programming, and I find it quite hard to find

Answer 1

A callback function is "A reference to executable code, or a piece of executable code, that is passed as an argument to other code."

Here is a good article to help understand what is a "callback" function.