Definition of: pyroxene

(pī′rok·sēn) noun
1. A monoclinic mineral, usually in short, prismatic crystals, composed principally of calcium and magnesium: next to feldspar, the most frequent component of igneous rocks.
2. Any member of the pyroxene group, as diopside and augite: they are essentially metasilicates. [<F pyroxène <Gk. pyr, pyros fire + xenos a stranger; because at first considered alien to igneous rocks]
—py·rox·en·ic (pī′rok·sen′ik) adjective