Definitions
1.NounThe state or quality of being active; activeness."Pit row was abuzz with activity."
2.NounSomething done as an action or a movement."The activity for the morning was a walk to the store."
3.NounSomething 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."
4.NounThe lexical aspect (aktionsart) of verbs or predicates that change over time and have no natural end point.
5.NounThe number of radioactive decays per unit time. Unit for it: becquerel or curie
6.NounThe property of substances to react with other substances