gnomon

[ noh-mon ]

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.

gnomon

/ 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

Derived Forms

• gnoˈmonically, adverb
• gnoˈmonic, adjective

Word History and Origins

Origin of gnomon¹

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

Word History and Origins

Origin of gnomon¹

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

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

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

From Washington Post

A sundial uses a shadow cast by a thin rod called a gnomon on to a flat surface etched with different times.

From BBC

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

From Washington Post

Pytheas of Marseilles—who lived in the time of Alexander the Great, about 330 B.C.—measured the latitude of Marseilles by means of a gnomon, and found it to be about 42° 56′½.

From Project Gutenberg