Is “Tempo” a Scrabble word?

1.A frequency or rate.

2.A move which is part of one's own plan or strategy and forces, e.g. by means of a check or attacking a piece, the opponent to make a move which is not bad but of no use for him (the player gains a tempo, the opponent loses a tempo), or equivalently a player achieves the same result in fewer moves by one approach rather than another.

3.The timing advantage of being on lead, thus being first to initiate a strategy to develop tricks for one's side.