sarcostyle vs fibril

sarcostyle and fibril both are nouns.

Word	Noun	Adjective	Verb	Adverb
sarcostyle	Yes	No	No	No
fibril	Yes	No	No	No

As nouns, fibril is a hypernym of sarcostyle; that is, fibril is a word with a broader meaning than sarcostyle:

sarcostyle: one of many contractile filaments that make up a striated muscle fiber
fibril: a very slender natural or synthetic fiber

Other hypernyms of sarcostyle include filament, strand.

sarcostyle (noun)	fibril (noun)
one of many contractile filaments that make up a striated muscle fiber	a very slender natural or synthetic fiber