An archaic word that is only ever used in conjunction with "and behold". In conjunction with the aforementioned words it means "look" or "what happened was".
I rammed my cock in her ass and, lo and behold, she started giving my grief.
Short for Polo. Back in the day, Lo-Lifes, Ralphies' Kids, and Polo USA (United Shoplifters Association) would run into stores in NYC and rack madd Lo gear. This is a purely New York City phenomenon.
Also: Kanye West may seem like a Lo head, but he's not. He's a new jack to the game.