A performance comprises an event in which generally one group of people (the performer or performers) behave in a particular way for the benefit of another group of people (the viewer or viewers, or audience). Sometimes the dividing line between performer and audience may become blurred, as in the example of "participatory theatre" where audience members might get involved in the theatrical event.
Performances might take place daily, or at some other regular interval.
Similar activties can take place in a religious or occult setting whereby the performance becomes a ritual. In a scientific setting, the carrying out of predetermined actionss in a controlled environment becomes the performance (execution) of an experiment.
A music performance (a concert or a recital) may take place indoors in a concert hall or outdoors in a field, and may require the audience to remain very quiet, or encourage them to sing and dance along with the music. In a street concert by one or more streetmusicians, often the public consists of people who happen to pass by. Such performers do not require payment, but do welcome it. See extended technique.
Similarly other street artists may carry out street performances, e.g. performing acrobatics. The same applies in other public places.
The word performance may also describe the way in which an actor(ess), or artiste in such a production performs. Or in a solo capacity; such as a mime artist, comedian, conjurer, etc.
In engineering, performance relates to measuring some output or behaviour. Techniques for monitoring performance include: