POP stands for Post Office Protocol. This is a protocol used to retrieve e-mail from a mail server. Most e-mail applications use the POP protocol. The newest and most widely used version of POP email is POP3 email. IMAP is another internet standard protocols for e-mail retrieval. You will see the term POP3 / IMAP in most of the web hosting plans available today.
The difference between POP3 / IMAP
POP3 will download all the messages to your computer while IMAP leaves a copy on the server until the user explicitly deletes them.
