1. the state or process of acting or doing: the medical team went into action.
2. something done or accomplished; a deed. see usage note at act.
3. organized activity to accomplish an objective: a problem requiring drastic action.
4. the causation of change by the exertion of power or a natural process: the action of waves on a beach; the action of a drug on blood pressure.
5. A movement or a series of movements, as of an actor.
6. manner of movement: a horse with fine action.
7. habitual or vigorous activity; energy: a woman of action.
8. behavior or conduct. often used in the plural.
9. the operating parts of a mechanism.
10. the manner in which such parts operate.
11. the manner in which a musical instrument can be played; playability: a piano with quick action.
12. the series of events and episodes that form the plot of a story or play.
13. the appearance of animation of a figure in painting or sculpture.
14. law A judicial proceeding whose purpose is to obtain relief at the hands of a court.
15. armed encounter; combat: missing in action.
16. an engagement between troops or ships: fought a rear-guard action.
17. the most important or exciting work or activity in a specific field or area: always heads for where the action is.

1. something done so as to accomplish a purpose.
2. A way of motion or functioning.
3. A fast-paced activity.
4. A mechanism; a moving part or assembly.
5. sexual intercourse.
6. the distance separating the strings and the fretboard on the guitar.
7. combat.
8. A charge or other process in a law court (also called lawsuit and actio).
9. A homomorphism from a group to a group of automorphisms.
10. demanding or signifying the start of something, usually an act or scene of a theatric performance.
11. to act on a request etc, in order to put it into effect.
12. to initiate a legal action against someone.

1. A process or condition of acting or moving, as opposed to rest; the doing of something; exertion of power or force, as when one body acts on another; the effect of power exerted on one body by another; agency; activity; operation
2. an act; a thing done; a deed; an enterprise. (pl.): habitual deeds; hence, conduct; behavior; demeanor.
3. the event or connected series of events, either real or imaginary, forming the subject of a play, poem, or other composition; the unfolding of the drama of events.
4. movement.
5. effective motion; also, mechanism.
6. any one of the active processes going on in an organism; the performance of a function.
7. gesticulation; the external deportment of the speaker, or the suiting of his attitude, voice, gestures, and countenance, to the subject, or to the feelings.
8. the attitude or position of the several parts of the body as expressive of the sentiment or passion depicted.
9.
10. A suit or process, by which a demand is made of a right in a court of justice; in a broad sense, 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.
11. A right of action.
12. A share in the capital stock of a joint-stock company, or in the public funds; hence, in the plural, equivalent to stocks.
13. an engagement between troops in war, whether on land or water; a battle; a fight.
14. the mechanical contrivance by means of which the impulse of the player's finger is transmitted to the strings of a pianoforte or to the valve of an organ pipe.

1. to bring a legal action against.
2. the process or state of acting or of being active, as opposed to rest; change of which the cause lies within the subject; activity; active exertion; energy manifested in outward acts, as contrasted with contemplation, speculation, speaking, or writing: as, a man of action.
3. an event considered as predicated of its cause; an act, usually in a complex or an inclusive sense; that which is done about or in relation to anything; a specific performance, proceeding, or course of conduct: as, a good or a bad action; actions speak louder than words; the action of a deliberative body.
4. an exertion of power or force; the real relation of a cause to its effect; causality; influence; agency; operation; impulse: as, the action of wind upon a ship's sails.
5. manner of moving; kind of motion or physical performance: as, this horse has fine action; the action of a machine.
6. in rhetoric, gesture or gesticulation; the deportment of the speaker, or the accommodation of his attitude, voice, gestures, and countenance to the subject, or to the thoughts and feelings expressed.
7. in poetry and the drama, the connected series of events on which the interest of the piece depends; the main subject or story, as distinguished from an incidental action or episode. unity of action is one of the dramatic unities.
8. in physiology: any one of the active processes going on in an organized body; some manifestation of vital activity; the performance of a function: as, the action of the stomach or the gastric juice on the food; a morbid action of the liver.
9. A more or less complex muscular effort.
10. in law: A proceeding instituted in court by one or more parties against another or others to enforce a right, or punish or redress a wrong: distinguished from judicial proceedings which are not controversial in form, as the probate of a will.
11. such a proceeding under the forms of the common law, as distinguished from a chancery suit and a criminal prosecution.
12. the right of bringing an action: as, the law gives an action for every claim.
13. in the fine arts: the appearance of animation, movement, or passion given to figures by their attitude, position, or expression, either singly or concurrently.
14. the event or episode represented or illustrated by a work of art.
15. A military fight; a minor engagement between armed bodies of men, whether on land or water: of less importance than a battle. see battle.
16. in machinery: the mechanism of a breech-loading gun by which it is opened to receive the charge.
17. that part of the mechanism of a pianoforte, an organ, or other similar instrument by which the action of the fingers upon the keys is transmitted to the strings, reeds, etc.
18. A share in the capital stock of a company; in the plural, stocks, or shares of stock.
19. in firearms, when the locks are bedded into the stock alone. E. H. knight.
20.
21.
22. in mech., the sum of the average momenta of the elements of a moving system, each multiplied by the distance through which it moves.
23. in dynamo-electric machines, wasteful internal circuits in the pole-pieces or cores; eddy, parasitic, or Foucault currents.

1. put in effect
2. the state of being active
3. the trait of being active and energetic and forceful
4. institute legal proceedings against; file a suit against
5. a judicial proceeding brought by one party against another; one party prosecutes another for a wrong done or for protection of a right or for prevention of a wrong
6. the most important or interesting work or activity in a specific area or field
7. the operating part that transmits power to a mechanism
8. a military engagement
9. a process existing in or produced by nature (rather than by the intent of human beings)
10. the series of events that form a plot
11. something done (usually as opposed to something said)
12. an act by a government body or supranational organization