FOLIUM

Fo″li‐um (?), n.; pl. E. Foliums (#), L. Folia (#). [] 1. 1. A leaf, esp. a thin leaf or plate.
2. 2. (Geom.) A curve of the third order, consisting of two infinite branches, which have a common asymptote. The curve has a double point, and a leaf-shaped loop; whence the name. Its equation is x3 + y3 = axy.