archiannelid vs annelid

archiannelid and annelid both are nouns.

Word	Noun	Adjective	Verb	Adverb
archiannelid	Yes	No	No	No
annelid	Yes	Yes	No	No

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

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

Other hypernyms of archiannelid include annelid worm, segmented worm.

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

archiannelid (adjective)	annelid (adjective)
	relating to or belonging to or characteristic of any worms of the phylum Annelida