gnomon

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. An [[object#Noun|object]] such as a [[pillar]] or a [[rod]] that is used to [[tell#Verb|tell]] [[time#Noun|time]] by the [[shadow#Noun|shadow]] it [[cast#Verb|casts]] when the [[sun#Noun|sun]] [[shine#Verb|shines]] on it, especially the [[pointer]] on a [[sundial]]. {{defdate|from mid 16th c.}}
2. An object such as a pillar used by an [[observer]] to [[calculate]] the [[meridian]] [[altitude]] of the sun (that is, the altitude of the sun when it [[reach#Verb|reaches]] the observer's meridian), for the purpose of [[determine|determining]] the observer's [[latitude]].
3. The [[index#Noun|index]] of the [[hour circle]] of a [[globe]].
4. {{lb|en|geometry}} A [[plane#Adjective|plane]] [[figure#Noun|figure]] [[form#Verb|formed]] by [[remove#Verb|removing]] a [[parallelogram]] from a [[corner#Noun|corner]] of a larger parallelogram.
5. {{lb|en|mathematics|by extension}} A [[number#Noun|number]] [[represent]]ing the [[increment#Noun|increment]] between two {{l|en|figurate number|figurate numbers|numbers [[equal#Adjective|equal]] to the numbers of [[dot#Noun|dots]] in [[geometric]] figures formed of dots}}.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.