• synonyms


noun Geology.
  1. rock forming the natural boundary of a plateau or other rise.
  2. bedrock forming the natural boundary of a placer or of a gravel deposit.
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Origin of rimrock

An Americanism dating back to 1855–60; rim + rock1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for rimrock

Historical Examples

  • We followed along the ledge around the rimrock until we came to a little pass through.

    Pluck on the Long Trail

    Edwin L. Sabin

  • On either side were brownish red jagged peaks and rimrock faces, specked with snow.

  • One after another they leaped over the edge of the rimrock until most of the flock was destroyed.

    The Story of Wool

    Sara Ware Bassett

  • The rimrock and the gravels above and below it constitute the Rattlesnake Formation.

British Dictionary definitions for rimrock


  1. rock forming the boundaries of a sandy or gravelly alluvial deposit
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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