a hard, readily cut and polished rubber, obtained by vulcanizing rubber with a large amount of sulfur, used in the manufacture of combs, buttons, and for electric insulation.
eb·on·ite (ěb'ə-nīt') n. A relatively inelastic rubber, made by vulcanization with a large amount of sulfur and used as an electrical insulating material.
(ěb'ə-nīt') 
əˌnaɪt