What is the full form of pen?

PEN doesn't have a full form in the traditional sense. It's a standalone word that originated from the Latin word "penna," meaning "feather."

However, in some contexts, PEN can be an abbreviation for:

* PEN International: A worldwide writers' association promoting literature and freedom of expression.

* Personal Identification Number: A unique code used for identification purposes.

* Pre-Existing Condition: A medical condition that existed before a person started a new health insurance plan.

So, depending on the context, PEN could have different meanings.