General Chess Terms | Part 1
Check
Check occurs when a piece is attacking either the white or black king. The king must move immediately or the piece attacking the king must be taken immediately to get away from check. A player does not need to call out check in order for it to occur.
Double check
Double check occurs when two pieces are attacking/checking the king at the same time. When double check occurs, the king must move because both pieces cannot be taken at the same time.
See also