archiannelid vs segmented worm

archiannelid and segmented worm both are nouns.

Word	Noun	Adjective	Verb	Adverb
archiannelid	Yes	No	No	No
segmented worm	Yes	No	No	No

As nouns, segmented worm is a hypernym of archiannelid; that is, segmented worm is a word with a broader meaning than archiannelid:

archiannelid: small primitive marine worm lacking external segmentation and resembling polychaete larvae
segmented worm: worms with cylindrical bodies segmented both internally and externally

Other hypernyms of archiannelid include annelid, annelid worm.

archiannelid (noun)	segmented worm (noun)
small primitive marine worm lacking external segmentation and resembling polychaete larvae	worms with cylindrical bodies segmented both internally and externally