TopPokerShop
Behind
1. An underdog; has outs remaining but would not win on a showdown without improvement.
"I figured I was behind, but I had a draw and the pot odds were enough for me to make the call."

2. In a seat position that acts after another particular player.
"I got lucky and was seated behind the maniac, rather than ahead of him."

3. A player who is losing. Has less chips than the average stack in a tourney.
"I'm so far behind. The blinds are getting pretty high so I need to make a move soon."

 
Australian Poker Weekly