n.
Any of various dark, granite-textured, crystalline rocks rich in plagioclase and having little quartz.
[French, from Greek diorizein, to distinguish : dia-, apart, between; see dia- + horizein, to divide, limit; see horizon.]
dioritic di'o·rit'ic (-rĭt'ĭk) adj.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
