composition board vs packing

composition board and packing both are nouns.

Word	Noun	Adjective	Verb	Adverb
composition board	Yes	No	No	No
packing	Yes	No	No	No

As nouns, packing is a hypernym of composition board; that is, packing is a word with a broader meaning than composition board:

Other hypernyms of composition board include paper, packing material, wadding.

composition board (noun)	packing (noun)
a stiff moderately thick paper	the enclosure of something in a package or box
	carrying something in a pack on the back
	any material used especially to protect something