What does "incombustible" mean?

Incombustible: Not combustible; not capable of being burned, decomposed, or consumed by fire; uninflammable; as, asbestus is an incombustible substance; carbon dioxide is an incombustible gas. Incombustible cloth, a tissue of amianthus or asbestus; also, a fabric imbued with an incombustible substance. -- In`com*bus"ti*ble*ness, n. -- In`com*bus"ti*bly, adv.

Sources