Watchword
From BiblePortal Wikipedia
Watchword [1]
(1):
(n.) A word given to sentinels, and to such as have occasion to visit the guards, used as a signal by which a friend is known from an enemy, or a person who has a right to pass the watch from one who has not; a countersign; a password.
(2):
(n.) A sentiment or motto; esp., one used as a rallying cry or a signal for action.