evacuation vs medevac

evacuation and medevac both are nouns.

Word	Noun	Adjective	Verb	Adverb
evacuation	Yes	No	No	No
medevac	Yes	No	No	No

As nouns, medevac is a hyponym of evacuation; that is, medevac is a word with a more specific, narrower meaning than evacuation:

evacuation: the act of evacuating; leaving a place in an orderly fashion; especially for protection
medevac: the evacuation of persons (usually by air transportation) to a place where they can receive medical care

Other hyponyms of evacuation include medical evacuation, medivac.

evacuation (noun)	medevac (noun)
the act of removing the contents of something	the evacuation of persons (usually by air transportation) to a place where they can receive medical care
the act of evacuating; leaving a place in an orderly fashion; especially for protection
the bodily process of discharging waste matter