action

The effort of performing or doing something.

Something done, often so as to accomplish a purpose.

A way of motion or functioning.

Fast-paced activity.

The way in which a mechanical device acts when used; especially a firearm.

(firearms) The way in which cartridges are loaded, locked, and extracted from the mechanism.

(music) The mechanism, that is the set of moving mechanical parts, of a keyboard instrument, like a piano, which transfers the motion of the key to the sound-making device.

(music, lutherie) The distance separating the strings and the fretboard on a guitar or other string instrument.

(slang, typically with a quantifier) Sexual intercourse.

(military) Combat.

(law) A charge or other process in a law court (also called lawsuit and actio).

(mathematics) A mapping from a pairing of mathematical objects to one of them, respecting their individual structures. The pairing is typically a Cartesian product or a tensor product. The object that is not part of the output is said to act on the other object. In any given context, action is used as an abbreviation for a more fully named notion, like group action or left group action.

(physics) The product of energy and time, especially the product of the Lagrangian and time.

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.

(art, painting and sculpture) The attitude or position of the several parts of the body as expressive of the sentiment or passion depicted.

(bowling) spin put on the bowling ball.

(obsolete) A share in the capital stock of a joint-stock company, or in the public funds.

(religion) A religious performance or solemn function, i.e. action sermon, a sacramental sermon in the Scots Presbyterian Church.