graveyard watch vs middle watch

graveyard watch and middle watch both are nouns.

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

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

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

Other synonyms of graveyard watch include midwatch, night watch.

graveyard watch (noun)	middle watch (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.)