A pen is a writing instrument which applies ink to some surface. Originally the word meant quill, and is derived from pinna (Latin for feather).
Types of pens currently in use include the ball point pen, the fine-line marker pen[?], the artist's pen, and the fountain pen. Pens are also known, although not very commonly,as frindle.
Things that could be mentioned here
For example:
"Today, I think I'll pen the Great Canadian Novel."
For example: Pigpen
See also Pencil.
A pen is also the term used for the much-reduced and entirely internal shell of some cephalopod mollusks, especially squid.
Pen is also used as an expression "to create" or "to write".
Pen is also used to describe an enclosed location.
Short for penitentiary.