/ak tiv"i tee/ , n. , pl. activities .
1. the state or quality of being active: There was not much activity in the stock market today. He doesn't have enough physical activity in his life.
2. a specific deed, action, function, or sphere of action: social activities.
3. work, esp. in elementary grades at school, that involves direct experience by the student rather than textbook study.
4. energetic activity; animation; liveliness.
5. a use of energy or force; an active movement or operation.
6. normal mental or bodily power, function, or process.
7. Physical Chem. the capacity of a substance to react, corrected for the loss of reactivity due to the interaction of its constituents.
a. the number of atoms of a radioactive substance that disintegrate per unit of time, usually expressed in curies.
9. an organizational unit or the function it performs.
[ 1520-30; ( activitas. See ACTIVE, -ITY ]