Webster's Revised Unabridged Dictionary · 1913

Gabbro

Gabbro , noun

[Italian]

(Geology) A name originally given by the Italians to a kind of serpentine, later to the rock called euphotide, and now generally used for a coarsely crystalline, igneous rock consisting of lamellar pyroxene (diallage) and labradorite, with sometimes chrysolite (olivine gabbro).