barycenter vs center of mass

barycenter and center of mass both are nouns.

Word	Noun	Adjective	Verb	Adverb
barycenter	Yes	No	No	No
center of mass	Yes	No	No	No

As nouns, center of mass is a hypernym of barycenter; that is, center of mass is a word with a broader meaning than barycenter:

barycenter: (astronomy) the common center of mass around which two or more bodies revolve
center of mass: point representing the mean position of the matter in a body

Other hypernyms of barycenter include centre of mass.

barycenter (noun)	center of mass (noun)
(astronomy) the common center of mass around which two or more bodies revolve	point representing the mean position of the matter in a body