pencil

noun

1. (historical)A paintbrush.

   “But living art may not least part expresse, / Nor life-resembling pencill it can paynt[…].”

   “why is it not lawfull for every man to pourtray himself with his pen, as it was for him to doe it with a pensell?”

   “He requested three things of Sir Joshua Reynolds:—To forgive him thirty pounds which he had borrowed of him; to read the Bible; and never to use his pencil on a Sunday.”

2. A writing utensil with a graphite (commonly referred to as lead) shaft, usually blended with clay, clad in wood, and sharpened to a taper.
3. An aggregate or collection of rays of light, especially when diverging from, or converging to, a point.
4. 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.

   “When, by the pencil becoming oblique to the surface, the vergency produced on the pencil becomes changed, the primary and secondary focal points, V and H, separate […]”

   “A drillable robot is capable of placing its end link in any orientation in the pencil of planes containing its first link.”

   “Let l and m be two hyperparallel lines. All the transversals to l and m that form congruent corresponding angles with l and m lie in a pencil.”

5. (obsolete, rare)A small medicated bougie.
6. A small, thin tuft of hairs or feathers.

   “It is almost entirely of a slatey colour, with yellow bill and feet, but the feathers of the rump and upper tail-coverts each terminate in a rigid, glossy pencil or tuft of a vivid crimson.”

7. (abbreviation, alt-of, ellipsis)Ellipsis of power of the pencil.

   “And most important of all, Cully now had 'The Pencil', that most coveted of Las Vegas powers.”

verb

1. (transitive)To write (something) using a pencil.

   “I penciled (BrE: pencilled) a brief reminder in my notebook.”

   “She had hardly got back when she encountered a piece by Robert Trewe in the new number of her favourite magazine, which must have been written almost immediately before her visit to Solentsea, for it contained the very couplet she had seen pencilled on the wallpaper by the bed, and Mrs. Hooper had declared to be recent.”

2. (transitive)To mark with, or as if with, a pencil.

   “It pencilled each flower with rich and variegated hues, and threw over its exuberant foliage a vesture of emerald green.”