Dragon Fang

Dragon Fang is a bone.

Source
Dragon Fangs can be obtained as a drop from the following mobs:
 * Ice Dragon - Coerthas Western Highlands
 * Blood Dragon - The Churning Mists
 * Moss Dragon - The Churning Mists
 * Thunder Dragon - The Dravanian Forelands

Uses
Dragon Fangs are used in crafting the following items: