Cro·cus n.
 1. Bot. A genus of iridaceous plants, with pretty blossoms rising separately from the bulb or corm. Crocus vernus is one of the earliest of spring-blooming flowers; Crocus sativus produces the saffron, and blossoms in the autumn.
 2. Chem. A deep yellow powder; the oxide of some metal calcined to a red or deep yellow color; esp., the oxide of iron (Crocus of Mars or colcothar) thus produced from salts of iron, and used as a polishing powder.
 Crocus of Venus Old Chem., oxide of copper.

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