Editing Crescent (section)

==Shape==
[[File:Luno ebena geom combined.svg|thumb|Examples of [[Lune (geometry)|lune]]s in [[planar geometry]] (shaded areas). Examples in the top row can be considered crescent shapes, because the lune does not contain the center of the original (right-most) circular disk.]]
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 | caption1 =  Crescent moon (2012 photograph)
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 | caption2 = An astronomically correct crescent shape (shaded area), complemented by a ''[[gibbous]]'' shape (unshaded area).
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The crescent shape is a type of [[lune (geometry)|lune]], the latter consisting of a [[disk (mathematics)|circular disk]] with a portion of another disk removed from it, so that what remains is a shape enclosed by two circular [[arc (geometry)|arcs]] which intersect at two points. In a crescent, the enclosed shape does not include the center of the original disk.

The tapered regions towards the points of intersection of the two arcs are known as the "horns" of the crescent. The classical crescent shape has its horns pointing upward (and is often worn as horns when worn as a crown or diadem, e.g. in depictions of the lunar goddess, or in the headdress of Persian kings, etc.<ref>The new Moon at sunset and the old Moon at sunrise, when observed with horns pointing upward, is also known as "[[wet moon]]" in English, in an expression loaned from Hawaiian culture.</ref>

The word ''[[wikt:crescent|crescent]]'' is derived [[etymologically]] from the present participle of the Latin verb ''{{lang|la|crescere}}'' "to grow", technically denoting the waxing moon ({{lang|la|luna crescens}}). As seen from the northern hemisphere, the waxing Moon tends to appear with its horns pointing towards the left, and conversely the waning Moon with its horns pointing towards the right; the English word ''crescent'' may however refer to the shape regardless of its orientation, except for the technical language of [[blazon]]ing used in [[heraldry]], where the word "increscent" refers to a crescent shape with its horns to the left, and "decrescent" refers to one with its horns to the right, while the word "crescent" on its own denotes a crescent shape with horns pointing upward.<ref>Arthur Charles Fox-Davies, ''A Complete Guide to Heraldry'' (1909), p.&nbsp;289.  Online texts at https://archive.org/details/completeguidetoh00foxduoft or http://www7b.biglobe.ne.jp/~bprince/hr/foxdavies/index.htm .</ref>

The shape of the lit side of a spherical body (most notably the Moon) that appears to be less than half illuminated by the Sun as seen by the viewer appears in a different shape from what is generally termed a crescent in planar geometry: 
Assuming the [[Terminator (solar)|terminator]] lies on a [[great circle]], the crescent Moon will actually appear as the figure bounded by a half-[[ellipse]] and a half-circle, with the major axis of the ellipse coinciding with a diameter of the semicircle.

Unicode encodes a crescent (increscent) at U+263D (☽) and a decrescent at U+263E (☾).
The [[Miscellaneous Symbols and Pictographs]] block provides variants with faces as emoji: {{unichar|1F31B| first quarter moon with face}} and {{unichar|1F31C|last quarter moon with face}}.<!--crescent proper and crescent reversed missing?-->
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