activity

noun pl. activities

1. the quality or state of being active; action
2. energetic action; liveliness; alertness
3. a normal function of the body or mind
4. an active force
5. any specific action or pursuit: recreational activities
6. Chem.
   1. the ability to react with other chemicals
   2. a thermodynamic quantity which represents the effective concentration of a substance in a reacting chemical system
   3. optical activity