[ kawr-ner-stohn ]
See synonyms for cornerstone on
  1. a stone uniting two masonry walls at an intersection.

  2. a stone representing the nominal starting place in the construction of a monumental building, usually carved with the date and laid with appropriate ceremonies.

  1. something that is essential, indispensable, or basic: The cornerstone of democratic government is a free press.

  2. the chief foundation on which something is constructed or developed: The cornerstone of his argument was that all people are created equal.

Origin of cornerstone

Middle English word dating back to 1250–1300; see origin at corner, stone

Words Nearby cornerstone Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use cornerstone in a sentence

British Dictionary definitions for cornerstone


/ (ˈkɔːnəˌstəʊn) /

  1. a stone at the corner of a wall, uniting two intersecting walls; quoin

  2. a stone placed at the corner of a building during a ceremony to mark the start of construction

  1. a person or thing of prime importance; basis: the cornerstone of the whole argument

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