SIDS vs sudden infant death syndrome

SIDS and sudden infant death syndrome both are nouns.

Word	Noun	Adjective	Verb	Adverb
SIDS	Yes	No	No	No
sudden infant death syndrome	Yes	No	No	No

As nouns, SIDS and sudden infant death syndrome are synonyms defined as:

SIDS and sudden infant death syndrome: sudden and unexpected death of an apparently healthy infant during sleep

Other synonyms of SIDS include cot death, crib death, infant death.

SIDS (noun)	sudden infant death syndrome (noun)
sudden and unexpected death of an apparently healthy infant during sleep	sudden and unexpected death of an apparently healthy infant during sleep