Lock Meaning – Poker Hand That Can’t Lose Under Any Circumstances
A lock is a casino slang term for a hand that can’t be beaten. It’s most notably used in poker to describe a situation in which a player has the best hand that can be made with the exposed cards on the board.
For example, let’s say that you have pocket Kings, and the community board reads K, K, 10, 8, 5.
With no straight flush or royal flush options available, the best any other player left in the game can have is a full house. So, knowing this, your four-of-a-kind is an absolute lock in this situation.