Activity - (Webster's 1828 Dictionary)
ACTIV'ITY, n. The quality of being active; the active faculty; nimbleness; agility; also the habit of diligent and vigorous pursuit of business; as, a man of activity. It is applied to persons or things.
Sphere of activity, is the whole space in which the virtue, power, or influence of any object, is exerted.
To put in activity, a French phrase, for putting in action or employment.