Glossary · F
Foil
Also called foils, trefoil, quatrefoil, cinquefoil, multifoil
A lobe formed by the cusping of a circle or arch: three make a trefoil, four a quatrefoil, five a cinquefoil, many a multifoil.
See also: Cusp
Rules that use the word
Bar tracery: windows drawn with compasses. Instead of cutting separate openings through a plate of wall, fill the whole window arch with glass and divide it by slender stone bars (mullions below, and circles, foils and sub-arches above) set out with compasses from the centres of the window’s own arches.
Plate, geometric, curvilinear, perpendicular. Date a Gothic window by its tracery: openings pierced through a plate (twelfth century); geometric bar tracery of circles and foils (thirteenth); flowing curvilinear tracery of ogees and daggers (fourteenth); and, in England, perpendicular panel tracery with mullions running straight up into the arch (late fourteenth to sixteenth).
Where it appears in the book
In the chapters Romanesque and Gothic.
Nearby in the glossary
Five points · Flemish bond · Flute · Flying buttress · Folly · Form-finding · Four-centred arch · Four-iwan plan