hive of activity
A very busy place.
As more and more people arrived, the office became a hive of activity.
noun
The state or quality of being active; activeness.
Pit row was abuzz with activity.
Something done as an action or a movement.
The activity for the morning was a walk to the store.
Something done for pleasure or entertainment, especially one involving movement or an excursion.
An increasing number of sports activities are on offer at the university.
Quilting can be an enjoyable activity.
The lexical aspect (aktionsart) of verbs or predicates that change over time and have no natural end point.
[…]distinctions among states of affairs are reflected to a striking degree in distinctions among Aktionsart types. That is, situations are expressed by state verbs or predicates, events by achievement verbs or predicates, and actions by activity verbs or predicates.
The number of radioactive decays per unit time. Unit for it: becquerel or curie