pow·der (pou′dər) n. 1. A substance consisting of ground, pulverized, or otherwise finely dispersed solid particles. 2. Any of various preparations in the form of powder, as certain cosmetics and medicines. 3. A dry explosive mixture, such as gunpowder. 4. Light dry snow. tr.v. pow·dered, pow·der·ing, pow·ders 1. To turn into or produce as a ...