silk vs fabric

silk and fabric both are nouns.

Word	Noun	Adjective	Verb	Adverb
silk	Yes	No	No	No
fabric	Yes	No	No	No

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

silk: a fabric made from the fine threads produced by certain insect larvae
fabric: artifact made by weaving or felting or knitting or crocheting natural or synthetic fibers

Other hypernyms of silk include cloth, material, textile.

silk (noun)	fabric (noun)
a fabric made from the fine threads produced by certain insect larvae	artifact made by weaving or felting or knitting or crocheting natural or synthetic fibers
animal fibers produced by silkworms and other larvae that spin cocoons and by most spiders	the underlying structure