from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A fine-grained metamorphic rock composed of quartz, feldspar, mica, and other minerals, formed by the action of intrusive rock upon sedimentary rock, especially shale.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any of a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and rendered massive, hard, splintery, and in some cases exceedingly tough and durable.
from The Century Dictionary and Cyclopedia
- n. In petrography, a dense, aphanitic rock composed of feldspar, quartz, and other minerals, usually a product of the contact-metamorphism of an intrusive rock upon shale or other sedimentary rock. Sometimes called hornstone.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a fine-grained metamorphic rock formed by the action of heat on clay rocks
German : Horn, horn; see hornblende + Fels, rock, cliff (from Middle High German vels, from Old High German felis).(American Heritage® Dictionary of the English Language, Fourth Edition)
German, meaning "horn stone", after its frequent association with glacial "horn peaks" in the Alps. (Wiktionary)