gabbro

noun, plural gab·bros. Petrology.

1. a dark granular igneous rock composed essentially of labradorite and augite.

noun plural -bros

1. a dark coarse-grained basic plutonic igneous rock consisting of plagioclase feldspar, pyroxene, and often olivine

n.

type of igneous rock, 1837, from Italian (Tuscan) gabbro, from Latin glaber “bare, smooth, bald” (see glad).

1. A usually dark, coarse-grained igneous rock composed mostly of plagioclase feldspar and clinopyroxene, and sometimes olivine. Gabbro is the coarse-grained equivalent of basalt.