floodgate vs sluice valve

floodgate and sluice valve both are nouns.

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

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

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

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

floodgate (noun)	sluice valve (noun)
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
something that restrains a flood or outpouring