Pronunciation: (ō'pul),[key] —n. 1. a mineral, an amorphous form of silica, SiO2 with some water of hydration, found in many varieties and colors, including a form that is milky white.
2. an iridescent variety of this that is used as a gem.
3. a gem of this.
Pronunciation: (ō'pul),[key] —n. a female given name.