Definition of peen in English:


(also pein)


  • The end of a hammer head opposite the face, typically wedge-shaped, curved, or spherical.

    [in combination] ‘a ball-peen hammer’
    • ‘The other end is a ball-shaped peen for metal working.’
    • ‘Besides the two ball peens, a one pound scaling hammer and a ten and a half pound handled sledge were offered.’


  • 1 Strike with a hammer or the peen of a hammer.

    ‘each run of weld is peened before the next run is applied’
    • ‘It is important to peen the weld metal while hot to help eliminate shrinkage, warpage, and possibly cracks.’
    • ‘The entire massive plinth and the next solid moulding above it are left with a rough surface, dented by heavy hammers and not peened to a sheen.’
    • ‘Short welds using a wandering sequence should be used and the weld should be peened as quickly as possible after welding.’
    1. 1.1
      another term for shot-peen


Early 16th century (as a verb): probably of Scandinavian origin; compare with Swedish dialect pena (ut), Danish dialect pene (ud) beat (out).