polyandry vs polygamy

polyandry and polygamy both are nouns.

Word	Noun	Adjective	Verb	Adverb
polyandry	Yes	No	No	No
polygamy	Yes	No	No	No

As nouns, polygamy is a hypernym of polyandry; that is, polygamy is a word with a broader meaning than polyandry:

polyandry: the state of having more than one husband at a time
polygamy: the condition or practice of having more than one spouse at a time

polyandry (noun)	polygamy (noun)
the state of having more than one husband at a time	the condition or practice of having more than one spouse at a time