noun
1. any specific behavior
e.g. they avoided all recreational activity
2. the trait of being active
moving or acting rapidly and energetically
e.g. the level of activity declines with age
Synonym: activeness
3. an organic process that takes place in the body
e.g. respiratory activity
Synonym: bodily processbody processbodily function
4. a process existing in or produced by nature (rather than by the intent of human beings)
e.g. the action of natural forces
volcanic activity
Synonym: natural processnatural actionaction
5. the state of being active
e.g. his sphere of activity
he is out of action
Synonym: actionactiveness
6. (chemistry) the capacity of a substance to take part in a chemical reaction
e.g. catalytic activity