Definition of topaz

• n. - 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.
• n. - Either one of two species of large, brilliantly colored humming birds of the Topaza, of South America and the West Indies.