paradoxical sleep vs REM

paradoxical sleep and REM both are nouns.

Word	Noun	Adjective	Verb	Adverb
paradoxical sleep	Yes	No	No	No
REM	Yes	No	No	No

As nouns, paradoxical sleep and REM are synonyms defined as:

paradoxical sleep and REM: a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep

Other synonyms of paradoxical sleep include rapid eye movement, rapid eye movement sleep, REM sleep.

paradoxical sleep (noun)	REM (noun)
a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep	a recurring sleep state during which dreaming occurs; a state of rapidly shifting eye movements during sleep