ac·tiv·i·ty 
(ăk-tĭvĭ-tē)
(ăk-tĭvĭ-tē)n. pl. ac·tiv·i·ties
1. The state of being active.
2. Energetic action or movement; liveliness.
3.
a. A specified pursuit in which a person partakes.
b. An educational process or procedure intended to stimulate learning through actual experience.
4. The intensity of a radioactive source.
5. The ability to take part in a chemical reaction.
6. A physiological process: respiratory activity.