squid vs architeuthis

squid and architeuthis both are nouns.

Word	Noun	Adjective	Verb	Adverb
squid	Yes	No	No	No
architeuthis	Yes	No	No	No

As nouns, architeuthis is a hyponym of squid; that is, architeuthis is a word with a more specific, narrower meaning than squid:

squid: widely distributed fast-moving ten-armed cephalopod mollusk having a long tapered body with triangular tail fins
architeuthis: largest mollusk known about but never seen (to 60 feet long)

Other hyponyms of squid include loligo, ommastrephes, giant squid.

squid (noun)	architeuthis (noun)
widely distributed fast-moving ten-armed cephalopod mollusk having a long tapered body with triangular tail fins	largest mollusk known about but never seen (to 60 feet long)
(Italian cuisine) squid prepared as food