Event

An event is something which happens or takes place. An event is brief, possibly extremely brief. Not like a process, which takes time.

• Alternate meaning: an important activity, an item in a program, or the program as a whole.

Culture

• A special occasion, such as a wedding or other party, is a social event.

Science

• In physics (and in some kinds of philosophy), an event occurs at a point in time which can be distinguished because the state of the world changed. Something was different before and after the event.
• In special relativity (and general relativity), an event is a point in the spacetime continuum, i.e. it has a position in space and time.
• In experimental particle physics, an event refers to a set of elementary particle interactions recorded in a brief span of time.
• In probability a possible outcome of an experiment is called an elementary event, while a set of those (a subset of all) is called simply an event.
• In palaeontology, one speaks of extinction events.

Telecommunications

• In information processing, an event is a change in the properties received by an observer after being transmitted from an object.
• In computer science, an event is a software message that indicates something has happened. See event-driven programming. A number of protocols, such as MIDI, are also event-based.