neonatal intensive care unit vs NICU

neonatal intensive care unit and NICU both are nouns.

Word	Noun	Adjective	Verb	Adverb
neonatal intensive care unit	Yes	No	No	No
NICU	Yes	No	No	No

As nouns, neonatal intensive care unit and NICU are synonyms defined as:

neonatal intensive care unit and NICU: an intensive care unit designed with special equipment to care for premature or seriously ill newborn

neonatal intensive care unit (noun)	NICU (noun)
an intensive care unit designed with special equipment to care for premature or seriously ill newborn	an intensive care unit designed with special equipment to care for premature or seriously ill newborn