A hand with more than high-card value, e.g. pair or up. Usually used as the opposite of a draw: "I checkraised the flop with my flushdraw figuring I could get my opponents to lay down if they missed, but when Johnny made it three bets to go, I was sure he had a made hand."
In poker, a made hand is one that does not need improvement to win, in contrast to a drawing hand. For example in Draw poker, if you have two pairs, and your opponent is drawing for a straight or flush, you are said to have a made hand because even though you will be drawing a card just as he will, you can win even if you don't draw a card that improves your hand, while he cannot win unless he improves.