triumvirate vs threesome

triumvirate and threesome both are nouns.

Word	Noun	Adjective	Verb	Adverb
triumvirate	Yes	No	No	No
threesome	Yes	No	No	No

As nouns, threesome is a hypernym of triumvirate; that is, threesome is a word with a broader meaning than triumvirate:

triumvirate: a group of three men responsible for public administration or civil authority
threesome: three people considered as a unit

Other hypernyms of triumvirate include triad, trinity, trio.

triumvirate (noun)	threesome (noun)
a group of three men responsible for public administration or civil authority	three people considered as a unit
	the cardinal number that is the sum of one and one and one