Pen (noun)

1. A writing instrument with a metal nib or ball which releases ink onto paper.
2. An enclosure for livestock.

Origin:

Middle english: from old french penne, from latin penna "feather".

Examples:

1. She wrote her letter with a blue pen.
2. He signed the document with a black pen.
3. The goat was kept in a pen.
4. The pigs were in a dirty pen.
5. The pen was made of wood and had a metal gate.