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See more synonyms for gnomon on Thesaurus.com
  1. the raised part of a sundial that casts the shadow; a style.
  2. an early astronomical instrument consisting of a vertical shaft, column, or the like, for determining the altitude of the sun or the latitude of a position by measuring the length of its shadow cast at noon.
  3. Geometry. (formerly) the part of a parallelogram that remains after a similar parallelogram has been taken away from one of its corners.
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Origin of gnomon

1540–50; < Latin gnōmōn pin of a sundial < Greek gnṓmōn literally, interpreter, discerner
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for gnomon

Historical Examples

  • No doubt, however, it was a sun-dial, or gnomon of some kind.

    The Story of Eclipses

    George Chambers

  • The Gnomon is any one of the Diagonall with the two complements.

  • There is therefore in every Parallelogramme a double Gnomon; as in these two examples.

  • But I landed in the dark chamber of a Gnomon, waist-deep in loose wheat.

    Pharaoh's Broker

    Ellsworth Douglass

  • I mounted the only unsealed Gnomon and shouted down into its cavernous depths.

    Pharaoh's Broker

    Ellsworth Douglass

British Dictionary definitions for gnomon


  1. the stationary arm that projects the shadow on a sundial
  2. a geometric figure remaining after a parallelogram has been removed from one corner of a larger parallelogram
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Derived Formsgnomonic, adjectivegnomonically, adverb

Word Origin

C16: from Latin, from Greek: interpreter, from gignōskein to know
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

Word Origin and History for gnomon


"vertical shaft that tells time by the shadow it casts" (especially the triangular plate on a sundial), 1540s, from Latin gnomon, from Greek gnomon "indicator," literally "one who discerns," from gignoskein "to come to know" (see gnostic (adj.)).

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Online Etymology Dictionary, © 2010 Douglas Harper