action

1. The effort of performing or doing something. (countable, uncountable)
2. Something done, often so as to accomplish a purpose. (countable, uncountable)
3. A way of motion or functioning. (countable, uncountable) · Knead bread with a rocking action.
4. Fast-paced activity. (countable, uncountable) · a movie full of exciting action
5. The way in which a mechanical device acts when used; especially a firearm. (countable, uncountable) · Pressing a piano key causes the action of the hammer on the string.
6. The way in which cartridges are loaded, locked, and extracted from the mechanism. (countable, uncountable) · pump-action shotgun
7. A physical mechanism of a firearm or other device. (countable, uncountable)
8. 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. (countable, uncountable) · The run in bar 12 is almost impossible with this piano's heavy action.

Plural actions