1911 Encyclopædia Britannica/Quatrefoil
QUATREFOIL, in Gothic architecture, the piercing of tracery in a window or balustrade with small semicircular openings known as "foils"; the intersection of these foils is termed the cusp.
See also Quatrefoil on Wikipedia; and our 1911 Encyclopædia Britannica disclaimer.
QUATREFOIL, in Gothic architecture, the piercing of tracery in a window or balustrade with small semicircular openings known as "foils"; the intersection of these foils is termed the cusp.