noun either one of two species of large, brilliantly colored humming birds of the topaza, of south america and the west indies.
2. topaz ·noun 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.