A vault built on ribs radiating from the wall supports, such as a cantilever, semi-colum, ancillary column. Ribs are all of the same curve and spaced equidistantly, in a manner resembling a fan. Fan vault appeared in the second half of the fourteenth century, and was most often used in late gothic, so-called perpendicular style, which dominated English architecture in the fifteenth century.
fan vault in Cathedral of Gloucester, second half of the 14th century, England, photo Wikimedia Commons
fan vault in King’s College Chapel, beginning of the 16th century, Cambridge, England
reconstruction of the fan vault from the beginning of the 16th century, Bath Abbey, England
reconstruction of the fan vault from the beginning of the 16th century, Bath Abbey, England, photo Wikimedia Commons