from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A light-colored igneous rock consisting essentially of alkali feldspar.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A pale igneous rock consisting mostly of potassium feldspar and plagioclase.
from the GNU version of the Collaborative International Dictionary of English
- n. An igneous rock, usually light gray in color and breaking with a rough surface. It consists chiefly of orthoclase feldspar with sometimes hornblende and mica.
from The Century Dictionary and Cyclopedia
- n. A volcanic rock exhibiting a characteristic roughness when handled.
French, from Greek trākhus, rough.(American Heritage® Dictionary of the English Language, Fourth Edition)
From French trachyte, from Ancient Greek τρᾱχύς ("rough"). (Wiktionary)