Christmas box vs gratuity

Christmas box and gratuity both are nouns.

Word	Noun	Adjective	Verb	Adverb
Christmas box	Yes	No	No	No
gratuity	Yes	No	No	No

As nouns, gratuity is a hypernym of Christmas box; that is, gratuity is a word with a broader meaning than Christmas box:

Christmas box: a present given at Christmas for services during the year
gratuity: a relatively small amount of money given for services rendered (as by a waiter)

Other hypernyms of Christmas box include backsheesh, baksheesh, bakshis, bakshish, pourboire, tip.

Christmas box (noun)	gratuity (noun)
a present given at Christmas for services during the year	a relatively small amount of money given for services rendered (as by a waiter)
	an award (as for meritorious service) given without claim or obligation