Word.ws English Dictionary

etendue

Syllables: eten·due/ˌeɪ.tɒnˈd(j)uː/US/ˌeɪ.tɑnˈdu/

etendue noun: a conserved property of the light in an optical system which characterizes how "spread out" the light is in terms of angle and area: it is the product of its cross-sectional area (normal to the direction of propagation) and the solid angle it subtends.

etendue: a conserved property of the light in an optical system which characterizes how "spread out" the...
Image: Jonathan Queutois, CC0, via Wikimedia Commons

Noun

etendue (uncountable)

  1. A conserved property of the light in an optical system which characterizes how "spread out" the light is in terms of angle and area: it is the product of its cross-sectional area (normal to the direction of propagation) and the solid angle it subtends.
    • The topics include […] carefully outlining the concepts of etendue, finesse, and their theoretical implications; methods of spectral, spatial, temporal, and polarization discrimination; and application of these topics to search and track systems.1966, “Advanced Infrared Technology [course title]”, in The University of Michigan Engineering Summer Conferences: Fundamentals of Infrared Technology, June 6–10, 1966; Advanced Infrared Technology...
    • The light power transmitted to the detector is proportional to the product of the solid angle #92;mathit#123;#92;Omega#125; and area A in the central plane, which is imaged by the lens onto the aperture (often called the étendue U).2003, Wolfgang Demtröder, “Spectroscopic Instrumentation”, in Laser Spectroscopy: Basic Concepts and Instrumentation (Advanced Texts in Physics), 3rd edition, Berlin: Springer-Verlag, →DOI, →ISBN...

Synonyms of etendue

Forms of etendue

alternative formétendue

Origin of etendue

Borrowed from French étendue (“area, expanse; size; extent, range, scale”), short for étendue géométrique (“geometric extent”).

Words that rhyme with etendue

48 more rhymesFewer rhymes

Questions about etendue

What does etendue mean?
Etendue means a conserved property of the light in an optical system which characterizes how "spread out" the light is in terms of angle and area: it is the product of its cross-sectional area (normal to the direction of propagation) and the solid angle it subtends.
What part of speech is etendue?
Etendue is a noun.
How do you pronounce etendue?
Etendue is pronounced /ˌeɪ.tɒnˈd(j)uː/ (UK).

Words near etendue in the dictionary

  1. ETDs
  2. etebenecid
  3. etegami
  4. etem
  5. Etemenanki
  6. etendue
  7. eteo-
  8. Eteoclus
  9. Eteocretan
  10. Eteocypriot
  11. eteostic

Source and license

Adapted from Wiktionary: etendue (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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