What is pens?

Depending on which variable of "pens" you would like, here are some:

* pen - a writing implement with a point from which ink flows * pen - an enclosure for confining livestock * pen - playpen: a portable enclosure in which babies may be left to play * pen - penitentiary: a correctional institution for those convicted of major crimes * pen - write: produce a literary work; "She composed a poem"; "He wrote four novels" * pen - female swan /The danswer