[ grey-wak, -wak-uh ]
/ ˈgreɪˌwæk, -ˌwæk ə /


Nearby words

  1. greylag,
  2. greylist,
  3. greyly,
  4. greynville,
  5. greys,
  6. greywether,
  7. grf,
  8. gribble,
  9. grice,
  10. grid


or grey·wacke

[ grey-wak, -wak-uh ]
/ ˈgreɪˌwæk, -ˌwæk ə /


Geology. a dark-gray coarse-grained wacke.

Origin of graywacke

1805–15; partly translation, partly adapted from German Grauwache; see wacke Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for greywacke

British Dictionary definitions for greywacke


US graywacke

/ (ˈɡreɪˌwækə) /


any dark sandstone or grit having a matrix of clay minerals

Word Origin for greywacke

C19: partial translation of German Grauwacke; see wacke

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for greywacke


[ grāwăk′, -wăk′ə ]

Any of various dark gray, coarse-grained sandstones that contain abundant feldspar and rock fragments and often have a clay-rich matrix. Graywackes are thought to originate in environments where erosion, transportation, and deposition happen so quickly that minerals and rock fragments do not have sufficient time to break down into finer constituents.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.