E-MAIL POP
A POP email is a mailbox on the server that waits for you like a dog waiting for a treat until you come and take all your emails.
My POP was like a dog waiting for a treat. It was full and I was annoyed.
I logged in and my POP had 200 emails. I was excited.
My cousin’s POP was empty because he took all the emails and left me with nothing.