What "tempo" means in chess

A tempo refers to a move that gains an advantage in development or time without losing any material or making any concessions. It is a concept used to measure the efficiency of a player's moves in terms of the number of moves required to achieve a particular goal. Essentially, a tempo is a turn or move that is gained or lost in the opening, middle or endgame that will determine the outcome of the game. A player can gain a tempo by moving a piece to a square that attacks the opponent's pieces, which in turn forces the opponent to respond to the threat, thus losing time.