graveyard watch vs midwatch

graveyard watch and midwatch both are nouns.

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

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

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

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

graveyard 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.)