silk cotton vs kapok

silk cotton and kapok both are nouns.

Word	Noun	Adjective	Verb	Adverb
silk cotton	Yes	No	No	No
kapok	Yes	No	No	No

As nouns, silk cotton and kapok are synonyms defined as:

silk cotton and kapok: a plant fiber from the kapok tree; used for stuffing and insulation

Other synonyms of silk cotton include vegetable silk.

silk cotton (noun)	kapok (noun)
a plant fiber from the kapok tree; used for stuffing and insulation	massive tropical tree with deep ridges on its massive trunk and bearing large pods of seeds covered with silky floss; source of the silky kapok fiber
	a plant fiber from the kapok tree; used for stuffing and insulation