To·paz n.
 1. Min. A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.
 2. Zool. Either one of two species of large, brilliantly colored humming birds of the genus Topaza (Topaza pella or Topaza pyra), of South America and the West Indies.
 Note: ☞ The two tail feathers next to the central ones are much longer that the rest, curved, and crossed. The Throat is metallic yellowish-green, with a tint like topaz in the center, the belly is bright crimson, the back bright red. Called also topaz hummer.
 False topaz. Min. See the Note under Quartz.
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