[ dahy-uh-beys ]
/ ˈdaɪ əˌbeɪs /

noun Petrology.

a fine-grained gabbro occurring as minor intrusions.
British. a dark igneous rock consisting essentially of augite and feldspar; an altered dolerite.

Origin of diabase

1810–20; < French, equivalent to dia- (error for di- two) + base base1

Related forms

di·a·ba·sic, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for diabase

British Dictionary definitions for diabase


/ (ˈdaɪəˌbeɪs) /


British an altered dolerite
US another name for dolerite

Derived Forms

diabasic, adjective

Word Origin for diabase

C19: from French, from Greek diabasis a crossing over, from diabainein to cross over, from dia- + bainein to go
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for diabase


[ dīə-bās′ ]

A dark-gray to black, medium-grained igneous rock consisting mainly of labradorite and pyroxene. Diabase is compositionally similar to andesite, but has coarser grains. It is commonly found in sills and dikes. Also called dolerite
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.