gallinule vs water hen

gallinule and water hen both are nouns.

Word	Noun	Adjective	Verb	Adverb
gallinule	Yes	No	No	No
water hen	Yes	No	No	No

As nouns, gallinule and water hen are synonyms defined as:

gallinule and water hen: any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens

Other synonyms of gallinule include marsh hen, swamphen.

gallinule (noun)	water hen (noun)
any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens	any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens
	a coot found in North America