NREM sleep vs nonrapid eye movement

NREM sleep and nonrapid eye movement both are nouns.

Word	Noun	Adjective	Verb	Adverb
NREM sleep	Yes	No	No	No
nonrapid eye movement	Yes	No	No	No

As nouns, NREM sleep and nonrapid eye movement are synonyms defined as:

NREM sleep and nonrapid eye movement: a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time

Other synonyms of NREM sleep include nonrapid eye movement sleep, NREM, orthodox sleep.

NREM sleep (noun)	nonrapid eye movement (noun)
a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time	a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur; accounts for about 75% of normal sleep time