Horseshoe arch

Emblematic arch common in Moorish architecture

The horseshoe arch, also called the Moorish arch and the keyhole arch, is a type of arch in which the circular curve is continued below the horizontal line of its diameter, so that the opening at the bottom of the arch is narrower than the arch's full span. Evidence for the earliest uses of this form are found in Late Antique and Sasanian architecture, and it was then used in Spain by the Visigoths. But in the 19th century, perhaps when these earlier uses had not been realized, it became emblematic of Islamic architecture, especially Moorish architecture and Mozarabic art in Iberia. It also made later appearances in Moorish Revival and Art Nouveau styles. Horseshoe arches can take rounded, pointed or lobed form.

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