emit

Emit is a verb meaning to send out or discharge something from a source. It is commonly used to describe the release of light, heat, sound, gas, radiation, or signals. The noun form emission refers to the act of emitting or to what is emitted. The word originates from the Latin emittere, meaning to send forth.

In physics, emission refers to the release of energy, often as photons or particles. Emission is a key concept in optics, where emission spectra reveal characteristic wavelengths, and in quantum mechanics, where spontaneous and stimulated emission govern light production. Temperature, energy levels, and the presence of an external field influence emission rates. In electronics, the term is also used to describe output signals or currents generated by a device.

In computing and software design, to emit means to generate and dispatch an event or notification. Event-driven architectures rely on components that emit events and others that listen for them. Languages and frameworks frequently provide an emit function or method, enabling loose coupling between producers and consumers of information.

Other uses include the emission of pollutants or scents, the release of radio waves, or the act of emitting a recorded sound in media production. The concept is generalized across disciplines as the act of producing or discharging something into the surrounding environment.