• synonyms


[ ahr-kohs ]
/ ˈɑr koʊs /


a granular sedimentary rock composed of quartz and feldspar or mica; a feldspathic sandstone.

Nearby words

arkansas stone, arkansas toothpick, arkansawyer, arkhangelsk, arkie, arkose, arkwright, arkwright furniture, arkwright, sir richard, arl, arlberg

Origin of arkose

Borrowed into English from French around 1830–40
Related formsar·ko·sic, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for arkose

  • The lowest cretaceous rocks yet found are composed of an arkose, derived in large part from the original igneous mass.

    The History of Cuba, vol. 1|Willis Fletcher Johnson
  • At the base there is often an arkose, composed largely of fragments of serpentine and granite derived from the ancient floor.

British Dictionary definitions for arkose


/ (ˈɑːkəʊs) /


a sandstone consisting of grains of feldspar and quartz cemented by a mixture of quartz and clay minerals

Word Origin for arkose

C19: from French
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 arkose


[ ärkōs ]

A usually pinkish or red sandstone consisting primarily of quartz and feldspar. Arkose usually forms as the result of the rapid disintegration of granite in areas of vigorous erosion. Its grains are usually angular and poorly sorted (mixed randomly in differing sizes).
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.