from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Any of various dark gray sandstones that contain shale.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Alternative form of greywacke.

from the GNU version of the Collaborative International Dictionary of English

  • n. A conglomerate or grit rock, consisting of rounded pebbles and sand firmly united together.

from The Century Dictionary and Cyclopedia

  • n. In geology, a compact aggregate of rounded or subangular grains of various silicious rocks, held together by a paste which is usually silicious.


Partial translation of German Grauwacke : grau, gray + Wacke, rock (from Middle High German, from Old High German waggo, boulder; see wegh- in Indo-European roots).
(American Heritage® Dictionary of the English Language, Fourth Edition)



Log in or sign up to get involved in the conversation. It's quick and easy.