A writing utensil with a graphite (commonly referred to as lead) shaft, usually blended with clay, clad in wood, and sharpened to a taper.
A paintbrush.
A family of geometric objects with a common property, such as the set of lines that pass through a given point in a projective plane.
An aggregate or collection of rays of light, especially when diverging from, or converging to, a point.
To write (something) using a pencil.
To mark with, or as if with, a pencil.
A hemihydrate of calcium sulfate, made by calcining gypsum, that hardens when moistened and allowed to dry; used to make casts, molds and sculpture.