Tempo (chess)
From Conservapedia
A tempo in chess is a single move, or turn by a player. Forcing an opponent to "lose a tempo" means causing him to waste a move by retreating to avoid losing material.
Losing a tempo is harmful to a chess player in two ways: first, by losing time on the clock which can be scarce in speed chess, and second by enduring the opportunity cost of not being able to improve a position.
