Peen

Part of speech: noun (n.)

1. A round-edged, or hemispherical, end to the head of a hammer or sledge, used to stretch or bend metal by indentation.

2. The sharp-edged end of the head of a mason's hammer. [Spelt also pane, pein, and piend.]

Part of speech: verb (v.)

To draw, bend, or straighten, as metal, by blows with the peen of a hammer or sledge.