meninx vs arachnoid

meninx and arachnoid both are nouns.

Word	Noun	Adjective	Verb	Adverb
meninx	Yes	No	No	No
arachnoid	Yes	Yes	No	No

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

Other hyponyms of meninx include leptomeninges, dura, dura mater, arachnoid membrane, pia mater.

meninx (noun)	arachnoid (noun)
a membrane (one of 3) that envelops the brain and spinal cord	air-breathing arthropods characterized by simple eyes and four pairs of legs
	the middle of the 3 meninges

meninx (adjective)	arachnoid (adjective)
	relating to or resembling a member of the class Arachnida