monogamy vs matrimony

monogamy and matrimony both are nouns.

Word	Noun	Adjective	Verb	Adverb
monogamy	Yes	No	No	No
matrimony	Yes	No	No	No

As nouns, matrimony is a hypernym of monogamy; that is, matrimony is a word with a broader meaning than monogamy:

monogamy: the practice or state of having only one spouse at a time
matrimony: the state of being a married couple voluntarily joined for life (or until divorce)

Other hypernyms of monogamy include marriage, spousal relationship, union, wedlock.

monogamy (noun)	matrimony (noun)
the practice or state of having only one spouse at a time	the ceremony or sacrament of marriage
	the state of being a married couple voluntarily joined for life (or until divorce)