from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of a common rock-forming series of triclinic feldspars, consisting of mixtures of sodium and calcium aluminum silicates. Also called oligoclase.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a group of aluminum silicate feldspathic minerals ranging in their ratio of calcium to sodium.
from the GNU version of the Collaborative International Dictionary of English
- n. A general term used of any triclinic feldspar. See the Note under feldspar.
from The Century Dictionary and Cyclopedia
- n. The name given by Breithaupt to the group of triclinie feldspars the two prominent cleavagedirections in which are oblique to each other.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any of a series of triclinic feldspars that form rocks
Greek plagio-, plagio- + Greek klasis, breaking (from its oblique cleavage) (from klān, to break).(American Heritage® Dictionary of the English Language, Fourth Edition)
From plagio- + -clase, after German Plagioklas. (Wiktionary)