pen

noun
  1. A writing instrument that uses ink to leave a mark on a surface, typically paper. noun
    She used a pen to sign the contract.
    He prefers writing with a fountain pen over a ballpoint pen.
  2. An enclosure for confining animals, especially livestock or poultry. noun
    The farmer built a new pen for the sheep.
    The chickens were kept in a pen to protect them from predators.
  3. To write or compose a piece of text, such as a letter, poem, or article. verb
    She penned a heartfelt letter to her friend.
    The author penned several best-selling novels.