Po Share definition Flag A slang word referring to faeces or taking a dump. More commonly used by the youth, it is a way of speaking about your waste without it sounding too unattractive. Before we go to the beach, I quickly need to make a po. Po by MickeyD=) August 23, 2012 0 0 Get merch Get the Po mug. Buy Now — $32.95 See more merch