the.com/quatrefoil

means A decorative shape made of four overlapping circles or lobes arranged around a center, like a stylized four-petaled flower.

from From French quatre ('four') plus feuille ('leaf'), itself from Latin quattuor and folium. It entered English in the medieval period as architects and stonemasons needed a word for the four-lobed tracery pattern they kept carving into Gothic windows and stone screens — a geometric cousin to the trefoil (three lobes) and cinquefoil (five), all borrowing the same leafy Latin root.