fishnet stockings vs stocking

fishnet stockings and stocking both are nouns.

Word	Noun	Adjective	Verb	Adverb
fishnet stockings	Yes	No	No	No
stocking	Yes	No	No	No

As nouns, stocking is a hypernym of fishnet stockings; that is, stocking is a word with a broader meaning than fishnet stockings:

fishnet stockings: leg coverings for women, made from an open mesh fabric resembling netting.
stocking: close-fitting hosiery to cover the foot and leg; come in matched pairs (usually used in the plural)

fishnet stockings (noun)	stocking (noun)
leg coverings for women, made from an open mesh fabric resembling netting.	the activity of supplying a stock of something
	close-fitting hosiery to cover the foot and leg; come in matched pairs (usually used in the plural)