Classification is the grouping of information to allow a person to achieve a goal or set purpose. The concept of an activity classifies at least three actions into a sequence of steps that produce an intentional goal. The concept of an activity enters the ACL scale in ACL 4.0.
I use the word activity in the general public sense and as a conceptual term to distinguish between actions and activities. To the general public, an activity is something that someone does and is a pursuit of some type such as interests, hobbies, pastimes and occupations. The distinction between an action and activity is common but not universal. In the ACL scale, an action is a particular motion that is not connected to the classification of an activity.