Pen, v. t. [imp. & p. p.Penned (?) or Pent (�); p. pr. & vb. n.Penning.] [OE. pennen, AS. pennan in on-pennan to unfasten, prob. from the same source as pin, and orig. meaning, to fasten with a peg.See Pin, n. & v.] To shut up, as in a pen or cage; to confine in a small inclosure or narrow space; to coop up, or shut in; to inclose. “Away with her, and pen her up.” Shak.
Watching where shepherds pen their flocks at eve. Milton.