evacuation vs medivac

evacuation and medivac both are nouns.

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

As nouns, medivac is a hyponym of evacuation; that is, medivac 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
medivac: the evacuation of persons (usually by air transportation) to a place where they can receive medical care

Other hyponyms of evacuation include medevac, medical evacuation.

evacuation (noun)	medivac (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