Atmospheric hammer

Hammer Ham"mer (h[a^]m"m[~e]r), n. [OE. hamer, AS. hamer, hamor; akin to D. hamer, G. & Dan. hammer, Sw. hammare, Icel. hamarr, hammer, crag, and perh. to Gr. 'a`kmwn anvil, Skr. a[,c]man 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. [1913 Webster]

With busy hammers closing rivets up. --Shak. [1913 Webster]

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. [1913 Webster]

He met the stern legionaries [of Rome] who had been the ``massive iron hammers'' of the whole earth. --J. H. Newman. [1913 Webster]

3. (Athletics) A spherical weight attached to a flexible handle and hurled from a mark or ring. The weight of head and handle is usually not less than 16 pounds. [Webster 1913 Suppl.]

{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} (Zo["o]l.), 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. [1913 Webster]