I. ˈpēn transitive verb
Date: 1513
: to draw, bend, or flatten by or as if by hammering with a peen
II. noun
Etymology: probably of Scandinavian origin; akin to Norwegian penn peen
Date: 1683
: a usually hemispherical or wedge-shaped end of the head of a hammer that is opposite the face and is used especially for bending, shaping, or cutting the material struck