Editing Trefoil (section)

==Architecture==
===Ornamentation===
'Trefoil' is a term in [[Gothic architecture]] given to the ornamental foliation or cusping introduced in the heads of window-lights, [[tracery]], and panellings, in which the centre takes the form of a three-lobed [[leaf]] (formed from three partially overlapping circles). One of the earliest examples is in the plate tracery at [[Winchester Cathedral]] (1222–1235). The fourfold version of an architectural trefoil is a [[quatrefoil]].

A simple trefoil shape in itself can be symbolic of the [[Trinity]],<ref>''Our Christian Symbols'' by Friedrich Rest ({{ISBN|0-8298-0099-9}}), p. 17</ref> while a trefoil combined with an equilateral triangle was also a moderately common symbol of the Christian Trinity during the [[late Middle Ages]] in some parts of Europe, similar to a [[quatrefoil#Barbed quatrefoil|barbed quatrefoil]]. Two forms of a trefoil combined with a triangle are shown below:

<gallery>
File:Trefoil-Architectural-Equilateral-Triangle-outlined.svg|alt=The outline of three interlocking circles with an equilateral triangle in the centre.|Outlined
File:Trefoil-Architectural-Equilateral-Triangle-interlaced.svg|alt=Three interlocking circles with a triangle in the centre, the full, interlocking lines of each now shown.|Interlaced
</gallery>

A [[Doves as symbols#Christianity|dove]], which symbolizes the [[Holy Spirit in Christianity|Holy Spirit]], is sometimes depicted within the outlined form of the trefoil combined with a triangle.

===Architectural layout===
In architecture and archaeology, a 'trefoil' describes a layout or [[floor plan]] consisting of three [[apse]]s in clover-leaf shape, as for example in the [[Megalithic temples of Malta]].

Particularly in church architecture, such a layout may be called a "triconchos".

<gallery>
File:Evolution du plan des temples copie.jpg|alt=A diagram of six examples of evolving temple floor plans, evolving clockwise, labelled {{lang|fr|Typologie des temples}} ("temple typology"). The floor plans evolve from small, simple rooms to much larger and more elaborate constructions.|Evolution of layout of Maltese Megalithic temples; [[Skorba Temples|Skorba]] (upper right) has a typical trefoil plan
File:Trikonchos.gif|alt=A triconchos floor plan, showing a wall with a door on the left side and three trefoil-like alcoves on the right.|A typical triconchos
</gallery>