silk vs animal fiber

silk and animal fiber both are nouns.

Word	Noun	Adjective	Verb	Adverb
silk	Yes	No	No	No
animal fiber	Yes	No	No	No

As nouns, animal fiber is a hypernym of silk; that is, animal fiber is a word with a broader meaning than silk:

silk: animal fibers produced by silkworms and other larvae that spin cocoons and by most spiders
animal fiber: fiber derived from animals

Other hypernyms of silk include animal fibre.

silk (noun)	animal fiber (noun)
a fabric made from the fine threads produced by certain insect larvae	fiber derived from animals
animal fibers produced by silkworms and other larvae that spin cocoons and by most spiders