Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun ham·mer \ˈha-mər\

Simple Definition of hammer

  • : a tool that has a heavy metal head attached to a handle and that is used for hitting nails or breaking things apart

  • : a similar tool made usually of wood and used especially for hitting a surface to make a loud noise

  • : the part of a gun that strikes a charge causing the gun to shoot

Source: Merriam-Webster's Learner's Dictionary

Full Definition of hammer

  1. 1 a :  a hand tool consisting of a solid head set crosswise on a handle and used for pounding b :  a power tool that often substitutes a metal block or a drill for the hammerhead

  2. 2 :  something that resembles a hammer in form or action: as a :  a lever with a striking head for ringing a bell or striking a gong b (1) :  an arm that strikes the cap in a percussion lock to ignite the propelling charge (2) :  a part of the action of a modern gun that strikes the primer of the cartridge in firing or that strikes the firing pin to ignite the cartridge c :  malleus d :  gavel e (1) :  a padded mallet in a piano action for striking a string (2) :  a hand mallet for playing on various percussion instruments (as a xylophone)

  3. 3 :  a metal sphere thrown for distance in the hammer throw

  4. 4 :  accelerator b

under the hammer

  1. :  for sale at auction

Origin and Etymology of hammer

Middle English hamer, from Old English hamor; akin to Old High German hamar hammer, and perhaps to Old Church Slavic kamen-, kamy stone, Greek akmē point, edge — more at edge

First Known Use: before 12th century



verb ham·mer

Simple Definition of hammer

  • : to force (something) into a particular place or shape by hitting it with a hammer

  • : to attach (something) with a hammer and nails

  • : to hit (something or someone) in a very forceful way

Source: Merriam-Webster's Learner's Dictionary

Full Definition of hammer



play \ˈha-mər-iŋ, ˈham-riŋ\
  1. intransitive verb
  2. 1 :  to strike blows especially repeatedly with or as if with a hammer :  pound

  3. 2 :  to make repeated efforts; especially :  to reiterate an opinion or attitude <the lectures all hammered away at the same points>

  4. transitive verb
  5. 1 a :  to beat, drive, or shape with repeated blows of a hammer b :  to fasten or build with a hammer

  6. 2 :  to strike or drive with a force suggesting a hammer blow or repeated blows <hammered the ball over the fence> <tried to hammer me into submission>

  7. 3 :  to criticize severely


play \ˈha-mər-ər\ noun

Examples of hammer in a sentence

  1. He hammered the dent out of the fender.

  2. The carpenters were hammering all afternoon.

  3. The workers are hammering the studs to the frame.

  4. The batter hammered the ball over the fence.

  5. Someone tried to hammer him over the head with a club.

  6. Many towns were hammered by the hurricane.

  7. The typist's fingers were hammering the keys.

  8. He was hammering at the door.

  9. The rain hammered down on the roof.

  10. The home team was hammered 9–0.

14th Century

First Known Use of hammer

14th century

HAMMER Defined for Kids



noun ham·mer \ˈha-mər\

Definition of hammer for Students

  1. 1 :  a tool consisting of a head fastened to a handle and used for pounding something (as a nail)

  2. 2 :  something like a hammer in shape or action <an auctioneer's hammer>

  3. 3 :  a heavy metal ball with a flexible handle thrown for distance in a track-and-field contest (hammer throw)



verb ham·mer

Definition of hammer for Students



  1. 1 :  to strike with a hammer

  2. 2 :  to fasten or build (as by nailing) with a hammer <Hammer the lid shut.>

  3. 3 :  to hit something hard and repeatedly <She hammered on the door.>

  4. 4 :  to beat hard <His heart hammered.>

hammer out

  1. :  to produce or bring about by persistent effort <“They hammered out those rules after the failure ten years ago.” — Lois Lowry, The Giver>

Medical Dictionary


noun ham·mer \ˈham-ər\

Medical Definition of hammer

Seen and Heard

What made you want to look up hammer? Please tell us where you read or heard it (including the quote, if possible).


a secret group of plotters

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which is a synonym of asperse?

defame placate divulge beat
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.