night watch vs midwatch

night watch and midwatch both are nouns.

Word	Noun	Adjective	Verb	Adverb
night watch	Yes	No	No	No
midwatch	Yes	No	No	No

As nouns, night watch and midwatch are synonyms defined as:

night watch and midwatch: a watch during the night (as from midnight to 8 a.m.)

Other synonyms of night watch include graveyard watch, middle watch.

night watch (noun)	midwatch (noun)
a watch during the night (as from midnight to 8 a.m.)	a watch during the night (as from midnight to 8 a.m.)