PO = Peace Out in short term.
Person #1: See ya later!
Person #2: Deuces!
Person #3: PO!
Further slangification of "p.o", an abbreviation of "Post Office".
"I'm going to check the po to see if I've got any college mail."
short for "hippo" or "hippopotamus"
I got this cute little 'po to add to my figurine collection!