Peen
Peen (pēn) , noun
[Compare German pinne pane of a hammer.]
(a)
A round-edged, or hemispherical, end to the head of a hammer or sledge, used to stretch or bend metal by indentation.
(b)
The sharp-edged end of the head of a mason's hammer.
Peen , transitive verb
To draw, bend, or straighten, as metal, by blows with the peen of a hammer or sledge.