What is Pen ?
Pen is (noun) 1. an object for writing with, using ink I’ve lost my red pen can I borrow yours? If you haven’t got a pen you can always write in pencil. ballpoint pen 2. a fenced enclosure for animals such as sheep They put the sheep in a pen overnight. Somehow the goats managed to get out of their pen. (verb) 1. to put animals such as sheep in a pen The sheep were penned while waiting to be taken to the market. 2. to be penned in to be in a small space, closely surrounded by other things or people She felt penned in, living in the same house as her husband’s parents. 3. to write something with a pen He penned a short letter to the local paper. (NOTE: penning penned)
source: Easier English, Student Dictionary Upper Intermediate Level