foam glass vs insulation

foam glass and insulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
foam glass	Yes	No	No	No
insulation	Yes	No	No	No

foam glass (noun)	insulation (noun)
Cellular glass, also called foam glass or expanded glass is a light, opaque, cellular glass made by adding powdered carbon to crushed glass and firing the mixture.	the act of protecting something by surrounding it with material that reduces or prevents the transmission of sound or heat or electricity
	the state of being isolated or detached
	insulating material that reduces or prevents the transmission of heat or sound or electricity