■ noun
1》 the process of doing something to achieve an aim.
↘the effect or influence of something such as a chemical.
2》 a thing done; an act.
3》 the way in which something works or moves.
4》 armed conflict.
5》 a lawsuit or legal proceedings.
■ verb take ~ on (something).
Phrases
in ~ engaged in an activity; in operation.
out of ~ not working.
Origin
ME: via OFr. from L. actio(n-) , from agere 'do, act'.