What is menopause?

I know it has something to do with girls and wahtever, but what is it

its when girls stop having periods when ther older

they stop having their period and often get hot flashes.

well
as you might alreday know (or not)
women are born with eggs
(what sperm fertilizes to make a baby)
when a woman gets older, around in her 50s
all of her eggs have been used up
so her period stops and she doesnt get it from then on

It usually doesn't happen in her 50's. It can happen, in rare cases earlier or most of the time later, like in their late 50's to 60's.