Ham″mer (–mẽr), n. [OE. hamer, AS. hamer, hamor; akin to D. hamer, G. & Dan. hammer, Sw. hammare, Icel. hamarr, hammer, crag, and perh. to Gr. ἄκμων anvil, Skr. açman stone.] 1. An instrument for driving nails, beating metals, and the like, consisting of a head, usually of steel or iron, fixed crosswise to a handle.
With busy hammers closing rivets up. Shak.
2. Something which in form or action resembles the common hammer; as: (a) That part of a clock which strikes upon the bell to indicate the hour. (b) The padded mallet of a piano, which strikes the wires, to produce the tones. (c) (Anat.) The malleus. See under Ear. (d) (Gun.) 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. (e) Also, a person or thing that smites or shatters; as, St. Augustine was the hammer of heresies.
He met the stern legionaries who had been the “massive iron hammers” of the whole earth. J. H. Newman.
Atmospheric hammer, a dead-stroke hammer in which the spring is formed by confined air. — Drop hammer, Face hammer, etc. See under Drop, Face, etc. — Hammer fish. See Hammerhead. — Hammer hardening, the process of hardening metal by hammering it when cold. — Hammer shell(Zoöl.), any species of Malleus, a genus of marine bivalve shells, allied to the pearl oysters, having the wings narrow and elongated, so as to give them a hammer-shaped outline; — called also hammer oyster. — To bring to the hammer, to put up at auction.