an instrument for driving nails, beating metals, and the like, consisting of a head, usually of steel or iron, fixed crosswise to a handle.-something which in firm or action resembles the common hammer-that part of a clock which strikes upon the bell to indicate the hour.-the padded mallet of a piano, which strikes the wires, to produce the tones.-the malleus.-that part of a gunlock which strikes the percussion cap, or firing pin; the cock; formerly, however, a piece of steel covering the pan of a flintlock musket and struck by the flint of the cock to ignite the priming.-also, a person of thing that smites or shatters; as, st. augustine was the hammer of heresies.-to beat with a hammer; to beat with heavy blows; as, to hammer iron.-to form or forge with a hammer; to shape by beating.-to form in the mind; to shape by hard intellectual labor; -- usually with out.-to be busy forming anything; to labor hard as if shaping something with a hammer.-to strike repeated blows, literally or figuratively.