kapok vs silk cotton

kapok and silk cotton both are nouns.

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

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

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

Other synonyms of kapok include vegetable silk.

kapok (noun)	silk cotton (noun)
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
a plant fiber from the kapok tree; used for stuffing and insulation