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buhrstone

[bur-stohn]
noun
  1. burstone.

burstone

or buhr·stone, burr·stone

[bur-stohn]
noun
  1. any of various siliceous rocks used for millstones.
  2. a millstone of such material.

Origin of burstone

bur(r)4 + stone
Also called buhr, burr.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for buhrstone

buhrstone

burstone or burrstone

noun
  1. a hard tough rock containing silica, fossils, and cavities, formerly used as a grindstone
  2. a grindstone or millstone made of this rock

Word Origin for buhrstone

C18 burr, perhaps identical to burr 1 (alluding to roughness)

burstone

noun
  1. a variant spelling of buhrstone
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