n.1. An instrument for writing or drawing with ink or similar fluid, especially:
a. A ballpoint pen.
b. A fountain pen.
c. A pen point.
d. A penholder and its pen point.
e. A quill.
2. a. An instrument for writing regarded as a means of expression: "Tyranny has no enemy so formidable as the pen" (William Cobbett).
b. A writer or an author: a hired pen.
c. A style of writing: wrote plays with a witty pen.
3. A pen-shaped device containing something other than ink: an insulin pen; a vaporizer pen.
4. Any of various other pen-shaped devices, such as a laser pointer.
5. The chitinous internal shell of a squid.
6. A pen shell.
7. pens Archaic The primary feathers or wings of a bird.