drainpipe vs cloaca

drainpipe and cloaca both are nouns.

Word	Noun	Adjective	Verb	Adverb
drainpipe	Yes	No	No	No
cloaca	Yes	No	No	No

As nouns, cloaca is a hyponym of drainpipe; that is, cloaca is a word with a more specific, narrower meaning than drainpipe:

Other hyponyms of drainpipe include culvert, scupper, sewer, sewerage, soil pipe, trap.

drainpipe (noun)	cloaca (noun)
a pipe through which liquid is carried away	a waste pipe that carries away sewage or surface water
	(zoology) the cavity (in birds, reptiles, amphibians, most fish, and monotremes but not other mammals) at the end of the digestive tract into which the intestinal, genital, and urinary tracts open