POP3 is a protocol used to receive mail from a server. Any mail client will be able to download with it.
Office installs outlook which supports pop3. you can also download 3rd party like thunderbird mail which also downloads pop3.
Maybe you are getting confused with "outlook express" which was in old versions of windows like XP, but still wasnt in 7. Or you have a windows 7 PC with office giving you outlook, and expecting that to be pre installed in windows, which its not.
