Inarchitecture, abifora is a type ofwindow divided vertically into two openings by a smallcolumn or amullion or apilaster; the openings are topped byarches,round orpointed.^[1][2][3] Sometimes the bifora is framed by a further arch; the space between the two arches may be decorated with a coat of arms or a small circular opening (oculus).

The bifora was used inByzantine architecture, including Italian buildings such as theBasilica of Sant'Apollinare Nuovo, inRavenna. Typical of theRomanesque andGothic periods, in which it became an ornamental motif for windows andbelfries, the bifora was also often used during theRenaissance period.^[4] InBaroque architecture andNeoclassical architecture the bifora was largely forgotten, or replaced by elements like the three openings of theVenetian window. It was also copied in theMoorish architecture in Spain, where it is calledajimez (from Arabicash-shammīs).^[5][6]

It returned in vogue in the nineteenth century in the period of eclecticism and rediscovery of the ancient styles inGothic Revival andRomanesque Revival architecture.

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  11th-century monastery ofHosios Loukas in Greece, representative of Byzantine style under theMacedonian dynasty
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  Alhambra,Granada
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  A Gothic bifora, Bochum-Stiepel (Germany)
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  A Romanic bifora,Casina,Oratorio di Beleo
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  Palazzo Strozzi,Florence
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  Campanile di Giotto,Florence
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  Palazzo del Granchio,Messina

• Monofora
• Trifora
• Quadrifora
• Polifora