gymnosperm vs seed plant

gymnosperm and seed plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
gymnosperm	Yes	No	No	No
seed plant	Yes	No	No	No

As nouns, seed plant is a hypernym of gymnosperm; that is, seed plant is a word with a broader meaning than gymnosperm:

gymnosperm: plants of the class Gymnospermae having seeds not enclosed in an ovary
seed plant: plant that reproduces by means of seeds not spores

Other hypernyms of gymnosperm include phanerogam, spermatophyte.

gymnosperm (noun)	seed plant (noun)
plants of the class Gymnospermae having seeds not enclosed in an ovary	plant that reproduces by means of seeds not spores