Gra*tu"i*ty (?), n.; pl. Gtratuities (#). [F. gratuit'e, or LL. gratuitas.]
1.
Something given freely or without recompense; a free gift; a present.
Swift.
2.
Something voluntarily given in return for a favor or service, as a recompense or acknowledgment.
<-- usually money. In particular, the money given to a waiter, cab driver, bellhop, etc. as a reward for good service = tip -->
© Webster 1913.