1. The state or process of acting or doing.

2. A deed. See Usage Note at act.

3. A movement or a series of movements.

4. Manner of movement: a horse with good action; a gearshift with smooth action.

5. Habitual or vigorous activity; energy: a woman of action.

6. Often actions Behavior or conduct.

7. a. The operating parts of a mechanism. b. The manner in which such parts operate.

8. A change that occurs in the body or in a bodily organ as a result of its functioning.

9. A physical change, as in position, mass, or energy, that an object or a system undergoes.

10. The series of events and episodes that form the plot of a story or play.

11. The appearance of animation of a figure in painting or sculpture.

12. Law. A judicial proceeding whose purpose is to obtain relief at the hands of a court.

13. Armed encounter; combat: killed in action.

14. The most important or exciting work or activity in a specific field or area: always heads for where the action is.