acarine vs arachnid

acarine and arachnid both are nouns.

Word	Noun	Adjective	Verb	Adverb
acarine	Yes	No	No	No
arachnid	Yes	No	No	No

As nouns, arachnid is a hypernym of acarine; that is, arachnid is a word with a broader meaning than acarine:

acarine: mite or tick
arachnid: air-breathing arthropods characterized by simple eyes and four pairs of legs

Other hypernyms of acarine include arachnoid.

acarine (noun)	arachnid (noun)
mite or tick	air-breathing arthropods characterized by simple eyes and four pairs of legs