departure vs difference

departure and difference both are nouns.

Word	Noun	Adjective	Verb	Adverb
departure	Yes	No	No	No
difference	Yes	No	No	No

As nouns, departure and difference are synonyms defined as:

departure and difference: a variation that deviates from the standard or norm

Other synonyms of departure include deviation, divergence.

departure (noun)	difference (noun)
the act of departing	the quality of being unlike or dissimilar
euphemistic expressions for death	a disagreement or argument about something important
a variation that deviates from the standard or norm	a variation that deviates from the standard or norm
	the number that remains after subtraction; the number that when added to the subtrahend gives the minuend
	a significant change