noun ac·tion \ ˈak-shən \
|Updated on: 9 Aug 2018

Definition of action

plural actions
1 a : a thing done : deed
b : the accomplishment of a thing usually over a period of time, in stages, or with the possibility of repetition
c actions plural : behavior, conduct
  • unscrupulous actions
d : initiative, enterprise
  • a man of action
2 : an act of will
  • an emergency requiring action
3 : the bringing about of an alteration by force or through a natural agency
  • the action of water on rocks
4 : the manner or method of performing:
a : an actor's or speaker's deportment or expression by means of attitude, voice, and gesture
  • An actor's words and actions should agree.
b : the style of movement of the feet and legs (as of a horse)
c : a function of the body or one of its parts
5 : the initiating of a proceeding in a court of justice by which one demands or enforces one's right; also : the proceeding itself
6 a (1) : an engagement between troops or ships
(2) : combat in war
  • gallantry in action
b (1) : an event or series of events forming a literary composition
  • Most of the play's action takes place in a courtroom.
(2) : the unfolding of the events of a drama or work of fiction : plot
  • As the action unfolds, we learn more about the hero's family.
(3) : the movement of incidents in a plot
  • a movie that is two hours of nonstop action
c : the combination of circumstances that constitute the subject matter of a painting or sculpture
7 a : an operating mechanism
b : the manner in which a mechanism or instrument operates
  • a drill's twisting action
8 a : the price movement and trading volume of a commodity, security, or market
b : the process of betting including the offering and acceptance of a bet and determination of a winner
c : financial gain or an opportunity for financial gain
  • a piece of the action
9 : sexual activity
10 : the most vigorous, productive, or exciting activity in a particular field, area, or group
  • wants to be where the action is
11 used as a director's command to start filming part of a movie or television show
  • Lights, camera, action!
12 : spin or rotation given to a ball or puck by throwing or hitting it in a particular way
  • If I am hitting into the wind on the 7th at Pebble Beach, … rather than taking an eight or a nine [iron] and hitting it hard, I'll choose a little eight or even a seven and almost chip the ball, putting as little action on it as possible so it lands softly and doesn't do a lot of spinning.
  • —Jack Nicklaus

Examples of action in a Sentence

  1. He was critical of the government's actions before the war.

  2. a military action against another country

  3. She tried to explain her actions.

  4. I accept full responsibility for my actions.

  5. The situation demanded immediate action.

  6. The problem may require military action.

  7. The school took disciplinary action against the drunken students.

  8. They decided that no further action was necessary.

Recent Examples of action from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'action.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of action

Middle English accioun, borrowed from Anglo-French accion, borrowed from Latin āctiōn-, āctiō "activity, act, legal process," from agere "to drive (cattle), cause to move, do" + -tiōn-, -tiō, noun suffix of verbal action — more at agent

ACTION Defined for Kids


noun ac·tion \ ˈak-shən \

Definition of action for Students

1 : the process by which something produces a change in another thing
  • the action of acid on metal
2 : the doing of something
  • Action is needed on this problem.
3 : something done
  • The mayor's first action was to call a meeting.
4 : the way something runs or works
  • the toy car's spinning action
5 : combat in war

Medical Dictionary


noun ac·tion \ ˈak-shən \

medical Definition of action

1 : the process of exerting a force or bringing about an effect that results from the inherent capacity of an agent
  • protein synthesis is an expression of gene action
  • insecticidal action
2 : a function or the performance of a function of the body (as defecation) or of one of its parts
  • the normal baby has three or four actions of the bowel in 24 hours
  • —Morris Fishbein
  • heart action
3 : an act of will
4 actions plural : behavior
  • aggressive actions

Law Dictionary


noun ac·tion

legal Definition of action

1 a : a judicial proceeding for the enforcement or protection of a right, the redress or prevention of a wrong, or the punishment of a public offense — compare special proceeding at proceeding
b : the right to bring or maintain such a legal or judicial proceeding
2 : an act or decision by an executive or legislative body of a government (as an administrative agency) or of an organization (as a Board of Directors)
  • the power of courts to invalidate statutes and executive actions
  • —R. H. Bork
3 : a voluntary act of will that manifests itself externally : a mode of conduct

Origin and Etymology of action

Latin actio legal proceeding, from agere to do, carry out, initiate legal proceedings

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