waste pipe vs cloaca

waste pipe and cloaca both are nouns.

Word	Noun	Adjective	Verb	Adverb
waste pipe	Yes	No	No	No
cloaca	Yes	No	No	No

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

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

waste pipe (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