amaranth vs caryopsis

amaranth and caryopsis both are nouns.

Word	Noun	Adjective	Verb	Adverb
amaranth	Yes	No	No	No
caryopsis	Yes	No	No	No

As nouns, caryopsis is a hypernym of amaranth; that is, caryopsis is a word with a broader meaning than amaranth:

amaranth: seed of amaranth plants used as a native cereal in Central and South America
caryopsis: dry seed-like fruit produced by the cereal grasses: e.g. wheat, barley, Indian corn

Other hypernyms of amaranth include grain.

amaranth (noun)	caryopsis (noun)
any of various plants of the genus Amaranthus having dense plumes of green or red flowers; often cultivated for food	dry seed-like fruit produced by the cereal grasses: e.g. wheat, barley, Indian corn
seed of amaranth plants used as a native cereal in Central and South America