Event

• A phenomenon, any observable occurrence, or an extraordinary occurrence

A type of gathering:

• A ceremony, for example, a marriage
• A competition, for example, a sports competition
• A convention (meeting)
• A happening, a performance or situation meant to be considered as art
• A festival, for example, a musical event
• A media event, a happening that attracts coverage by mass media
• A party
• A sporting event

In science, technology, and mathematics:

• Event (computing), a software message indicating that something has happened, such as a keystroke or mouse click
• Event, Particle accelerator, experiments which produce high energy (Electron volt|MeV, GeV, and TeV) subatomic particle collisions
• Event (probability theory), a set of outcomes to which a probability is assigned
• Event (UML), in Unified Modeling Language, a notable occurrence at a particular point in time
• Event chain methodology, in project management
• Event (relativity), a point in space at an instant in time, i.e. a location in spacetime
• Event horizon, a boundary in spacetime, typically surrounding a black hole, beyond which events cannot effect an exterior observer
• Extinction event, a sharp decrease in the number of species in a short period of time
• Celestial event, an astronomical phenomenon of interest

In philosophy:

• Event (philosophy), an object in time, or an instantiation of a property in an object
• Mental event, something that happens in the mind, such as a thought