What is a "pip" and what is a "zip"?

[chicklets81]

ok, I'm totally new to incubating. This Easter Hatch-a-long is my first time ever hatching chicken eggs.

I've heard people talk about a "pip" and "zip".

What are those things?

Someone educate me, he he.

 

[Poultry parent]

A pip is when a chick pokes a little hole in the egg for the first time, sipping is when the chick starts to peck around the circumference of the shell