chromatid vs fibril

chromatid and fibril both are nouns.

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

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

chromatid: one of two identical strands into which a chromosome splits during mitosis
fibril: a very slender natural or synthetic fiber

Other hypernyms of chromatid include filament, strand.

chromatid (noun)	fibril (noun)
one of two identical strands into which a chromosome splits during mitosis	a very slender natural or synthetic fiber