'Diabase' definitions:

Definition of 'Diabase'

From: GCIDE

Diabase \Di"a*base\, n. [F. diabase, fr. Gr. ? a crossing or passing over, fr. ?; ? + ? to go; -- so called by Brongniart, because it passes over to diorite.] (Min.) A basic, dark-colored, holocrystalline, igneous rock, consisting essentially of a triclinic feldspar and pyroxene with magnetic iron; -- often limited to rocks pretertiary in age. It includes part of what was early called greenstone. [1913 Webster]