knife vs seax

knife and seax both are nouns.

Word	Noun	Adjective	Verb	Adverb
knife	Yes	No	Yes	No
seax	Yes	No	No	No

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

knife: a weapon with a handle and blade with a sharp point
seax: a type of sword or dagger typical of the Germanic peoples of the Migration period and the Early Middle Ages, especially the Saxons.

Other hyponyms of knife include bayonet, dagger, sticker, khukuri, machete, matchet, panga, shiv, trench knife, yataghan, kindjal.

knife (noun)	seax (noun)
edge tool used as a cutting instrument; has a pointed blade with a sharp edge and a handle	a type of sword or dagger typical of the Germanic peoples of the Migration period and the Early Middle Ages, especially the Saxons.
a weapon with a handle and blade with a sharp point
any long thin projection that is transient

knife (verb)	seax (verb)
use a knife on