Po Share definition Flag Abbreviation of "pony"; a small horse (..and I'm right, because it's my name; Kelly-Po... :P). "Look at all the pos!" "That po is an American Quarter horse." "Smack the po with a crop if it is being lazy." Po by Kelly-Po September 13, 2003 0 0 Get merch Get the Po mug. Buy Now — $32.95 See more merch