CORUNDUM


Meaning of CORUNDUM in English

(n.) The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.

Webster's English dictionary.      Английский словарь Webster.