gnomon

American  

[noh-mon] / ˈnoʊ mɒn /

noun

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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gnomon British  

/ ˈnəʊmɒn /

noun

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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Other Word Forms

• gnomonic
  adjective
• gnomonically
  adverb

Etymology

Origin of gnomon

1540–50; < Latin gnōmōn pin of a sundial < Greek gnṓmōn literally, interpreter, discerner

Example Sentences

As visitors hover over the work, functioning as a vertical gnomon, their shadows fall onto one of the panels, depending on the time of day.

From Los Angeles Times • Aug. 4, 2023

The pole serves as a gnomon, the part of a sundial that casts a shadow to denote time.

From Washington Post • Apr. 17, 2020

A gnomon is the perpendicular part of a sundial, the part that casts a shadow.

From Washington Post • Jan. 10, 2018

He stooped again, and found the gnomon and pencil correct, and pressing on the pencil hard, drew it towards him out of the groove a little way.

From Bevis The Story of a Boy by Jefferies, Richard

Dials are of various construction, horizontal, inclined, or upright, the principle in every case being to show the sun's distance from the meridian by means of the shadow cast by the stile or gnomon.

From The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde by Various