Pronunciation: (pēn), [key]
a wedgelike, spherical, or other striking end of a hammer head opposite the face.
1. to enlarge, straighten, or smooth with a peen.
2. to strengthen (a metal surface) by light hammering or by bombardment with steel balls or shot.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.