penstock vs sluice valve

penstock and sluice valve both are nouns.

Word	Noun	Adjective	Verb	Adverb
penstock	Yes	No	No	No
sluice valve	Yes	No	No	No

As nouns, penstock and sluice valve are synonyms defined as:

penstock and sluice valve: regulator consisting of a valve or gate that controls the rate of water flow through a sluice

Other synonyms of penstock include floodgate, head gate, sluicegate, water gate.

penstock (noun)	sluice valve (noun)
conduit that carries a rapid flow of water controlled by a sluicegate	regulator consisting of a valve or gate that controls the rate of water flow through a sluice
regulator consisting of a valve or gate that controls the rate of water flow through a sluice