cistern vs cesspit

cistern and cesspit both are nouns.

Word	Noun	Adjective	Verb	Adverb
cistern	Yes	No	No	No
cesspit	Yes	No	No	No

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

cistern: an artificial reservoir for storing liquids; especially an underground tank for storing rainwater
cesspit: a covered cistern; waste water and sewage flow into it

Other hyponyms of cistern include cesspool, sink, sump, rain barrel.

cistern (noun)	cesspit (noun)
an artificial reservoir for storing liquids; especially an underground tank for storing rainwater	a covered cistern; waste water and sewage flow into it
a tank that holds the water used to flush a toilet
a sac or cavity containing fluid especially lymph or cerebrospinal fluid