hammer shell

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.
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            With busy hammers closing rivets up.  --Shak.
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   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.
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                He met the stern legionaries [of Rome] who had
                been the "massive iron hammers" of the whole
                earth.                            --J. H.
                                                  Newman.
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   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} (Zool.), 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.
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