How to explain callbacks in plain english? How are they different from calling one function from another function?

Question

How to explain callbacks in plain English? How are they different from calling one function from another function taking some context from the calling function? How can thei

Answer 1

Johny the programmer needs a stapler, so he goes down to the office supply department and ask for one, after filling the request form he can either stand there and wait for the clerk go look around the warehouse for the stapler (like a blocking function call) or go do something else meantime.

since this usually takes time, johny puts a note together with the request form asking them to call him when the stapler is ready for pickup, so meantime he can go do something else like napping on his desk.