| n. | 1. | A leaf, esp. a thin leaf or plate. |
| 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 |
| Noun | 1. | folium - a thin layer or stratum of (especially metamorphic) rock |