swamphen vs gallinule

swamphen and gallinule both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamphen	Yes	No	No	No
gallinule	Yes	No	No	No

As nouns, swamphen and gallinule are synonyms defined as:

swamphen and gallinule: 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 swamphen include marsh hen, water hen.

swamphen (noun)	gallinule (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