caoutchouc vs vulcanite

caoutchouc and vulcanite both are nouns.

Word	Noun	Adjective	Verb	Adverb
caoutchouc	Yes	No	No	No
vulcanite	Yes	No	No	No

As nouns, vulcanite is a hyponym of caoutchouc; that is, vulcanite is a word with a more specific, narrower meaning than caoutchouc:

caoutchouc: an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products
vulcanite: a hard nonresilient rubber formed by vulcanizing natural rubber

Other hyponyms of caoutchouc include foam rubber, crepe rubber, cold rubber, ebonite, hard rubber, Para rubber.

caoutchouc (noun)	vulcanite (noun)
an elastic material obtained from the latex sap of trees (especially trees of the genera Hevea and Ficus) that can be vulcanized and finished into a variety of products	a hard nonresilient rubber formed by vulcanizing natural rubber