Editing Extension

{{Wiktionary|extension|extend|extended}}

{{for|Wikipedia's extended confirmed protection|Wikipedia:Protection policy#extended|selfref=y}}

'''Extension''', '''extend''' or '''extended''' may refer to:

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==Mathematics==

===Logic or set theory===
* [[Axiom of extensionality]]
* [[Extensible cardinal]]
* [[Extension (model theory)]]
* [[Extension (proof theory)]]
* [[Extension (predicate logic)]], the set of tuples of values that satisfy the predicate
* [[Extension (semantics)]], the set of things to which a property applies
* [[Extension (simplicial set)]]
* [[Extension by definitions]]
* [[Extensional definition]], a definition that enumerates every individual a term applies to
* [[Extensionality]]

===Other uses===
* [[Extension of a function]], defined on a larger domain
* [[Extension of a polyhedron]], in geometry
* Extension of a [[line segment]] (finite) into an infinite line (e.g., [[extended base]])
* [[Exterior algebra]], Grassmann's theory of extension, in geometry
* [[Field extension]], in Galois theory
* [[Group extension]], in abstract algebra and homological algebra
* [[Homotopy extension property]], in topology
* [[Kolmogorov extension theorem]], in probability theory
* [[Linear extension]], in order theory
* [[Sheaf extension]], in algebraic geometry
* [[Tietze extension theorem]], in topology
* [[Whitney extension theorem]], in differential geometry

==Music==
* [[Extension (music)]], notes that fit outside the standard range
* [[Extended (Solar Fields album)|''Extended'' (Solar Fields album)]], 2005
* [[Extension (George Braith album)|''Extension'' (George Braith album)]], 1964
* [[Extension (Clare Fischer album)|''Extension'' (Clare Fischer album)]], 1963
* [[Extensions (Ahmad Jamal album)|''Extensions'' (Ahmad Jamal album)]], 1965
* ''Extensions'', a 1969 album by [[Mystic Moods Orchestra]]
* [[Extensions (McCoy Tyner album)|''Extensions'' (McCoy Tyner album)]], 1970
* [[Extensions (Dave Holland album)|''Extensions'' (Dave Holland album)]], 1988
* [[Extensions (The Manhattan Transfer album)|''Extensions'' (The Manhattan Transfer album)]], 1979
* Extension (The Extended Mixes), 2023 album reissue by [[Kylie Minogue]]

==Places==
* [[Extension, British Columbia]], a village near Regional District of Nanaimo, British Columbia, Canada
* [[Extension, Louisiana]], unincorporated community, United States

==Science==
* [[Extension (geology)]], relating to the pulling apart of the Earth's crust and lithosphere
* [[Extension (anatomy)]], a movement at a [[joint]] that increases the angle between the two ends of the joint; the opposite of [[flexion]]
* Extension locus, the gene locus of [[Melanocortin 1 receptor]]

==Other uses==
* [[Agricultural Extension]]
* [[Browser extension]], a small software module for customizing a web browser
* [[Renovation|Building extension]]
* [[Continuing education]], or extension school, a school for continuing education
* [[Cooperative State Research, Education, and Extension Service]], a former division of the U.S. Department of Agriculture
* [[Extension (metaphysics)]], the property of stretching out or taking up space
* [[Extension (telephone)]], telephone line attached to a main line or to a PBX or Centrex system
* [[Extension cord]], power cable with a plug on one end and one or more sockets on the other end 
* [[Eyelash extensions]], material applied to eyelashes
* [[Hair extensions]], strands of hair added to existing hair
* Extension, the building of community capacity by outsiders, for instance [[agricultural extension]]
* [[Filename extension]], for computer file systems

== See also ==
* [[Extensive (disambiguation)]]

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