from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A fine-grained extrusive volcanic rock, similar to granite in composition and usually exhibiting flow lines.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An igneous, volcanic (extrusive) rock, of felsic composition, with aphanitic to porphyritic texture.
from the GNU version of the Collaborative International Dictionary of English
- n. A quartzose trachyte, an igneous rock often showing a fluidal structure.
from The Century Dictionary and Cyclopedia
- n. The name given by Richthofen to certain rocks occurring in Hungary which resemble trachyte, but are distinguished from it by the presence of quartz as an essential ingredient, and also by a great variety of texture, showing more distinctly than rocks usually do that the material had flowed while in a viscous state.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. very acid volcanic rock
Greek rhuāx, stream (from rhein, to flow) + -lite.(American Heritage® Dictionary of the English Language, Fourth Edition)
Coined by Ferdinand von Richthofen as German Rhyolith, from Ancient Greek ῥέω (rheō, "flow") + -lith (modified to -lite). (Wiktionary)