etendue

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. {{lb|en|optics}} A [[conserved#Adjective|conserved]] [[property]] of the [[light#Noun|light]] in an [[optical]] [[system]] which [[characterize]]s how "spread out" the light is in terms of [[angle#Noun|angle]] and [[area]]: it is the [[product]] of its [[cross-sectional]] area ([[normal]] to the [[direction]] of [[propagation]]) and the [[solid angle]] it [[subtend]]s.

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