1. A hand tool consisting of a handle with a head of metal or other heavy rigid material that is attached at a right angle, used for striking or pounding.
2. A tool or device similar in function or action to this striking tool, as:
   1. The part of a gunlock that hits the primer or firing pin or explodes the percussion cap and causes the gun to fire.
   2. Music. One of the padded wooden pieces of a piano that strikes the strings.
   3. A part of an apparatus that strikes a gong or bell, as in a clock.
3. Anatomy. See malleus.
4. Sports. A metal ball weighing 16 pounds (7.2 kilograms) and having a long wire or wooden handle by which it is thrown for distance in track-and-field competition.
5. A small mallet used by auctioneers.

1. To hit, especially repeatedly, with or as if with a hammer; pound. See synonyms at beat.
2. To beat into a shape with or as if with a hammer: hammered out the dents in the fender; hammered out a contract acceptable to both sides.
3. To put together, fasten, or seal, particularly with nails, by hammering.
4. To force upon by constant repetition: hammered the information into the students' heads.
5. 1. To defeat soundly.
   2. To inflict a heavy loss or damage on.

1. To deal repeated blows with or as if with a hammer; pummel: "Wind hammered at us violently in gusts" (Thor Heyerdahl).
2. To undergo beating in the manner of a hammer: My pulse hammered.
3. Informal. To keep at something continuously: hammered away at the problem.

under the hammer

1. For sale at an auction.

[Middle English hamer, from Old English hamor.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.