fasciculus vs nervus

fasciculus and nervus both are nouns.

Word	Noun	Adjective	Verb	Adverb
fasciculus	Yes	No	No	No
nervus	Yes	No	No	No

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

fasciculus: a bundle of fibers (especially nerve fibers)
nervus: any bundle of nerve fibers running to various organs and tissues of the body

Other hyponyms of fasciculus include fornix, trigonum cerebrale, nerve.

fasciculus (noun)	nervus (noun)
a bundle of fibers (especially nerve fibers)	any bundle of nerve fibers running to various organs and tissues of the body