Peen may refer to: Part of the head of a hammer, as in a ball-peen hammer (also ball-pein, or ball and pein) Peening, the changing of a metal's properties by impacting its surface Shot peening, bombarding metal parts with small spherical media Shot peening of steel belts, a remedial solution for deformed steel belts Laser peening, focusing lasers on the surface of a metal part Peening (scythe blade), peening a scythe or sickle blade as a step in the sharpening process A slang term for penis
See also Peene (disambiguation) Pein Peen tong, a Chinese brown sugar and sugar candy