1. The act of causing to flow out: Tipping the filled water pitcher on its side caused the emission of all the water, which poured out onto the table.
2. The outpouring of a liquid from a pipe: When the farmer turned the water main on, there was an emission of water from the concrete conduit as it flowed into the orchard to water the trees.
3. The action of small particles or substances moving away from a central source: The emission of heat from the fireplace soon warmed the entire room.
4. One of a number of ways in which something may be discharged out of the body: Coughing is a way to facilitate the emission of phlegm from the throat.
5. Something that has been discharged or released from the body: Dr. Smith sent a sample of the emission of pus from the patient's wound to the laboratory to be analyzed.

1. The release of electrons from a specific material into the surrounding area or space.

It may be caused by an electric field, light, heat, or impact chemical disintegration.

2. A liberation of electrons from a substance into a vacuum.

Since all substances consist of atoms and since all atoms contain electrons, any substance may emit electrons; usually, however, the term refers to the emission of electrons from the surface of a solid.

3. The freeing of electrons into space from the surface of a body under the influence of heat, light, impact, chemical disintegration, or a potential difference.

1. Any spectrum produced by the emission of electromagnetic radiation by atoms, molecules, or ions, because of electron excitation or the signal voltage that is applied to the control electrode of an electron tube.
2. A spectrum resulting from the emission of electromagnetic radiation by ions, atoms, and molecules following excitations of their electrons.

A quantum transition between two energy levels of a nucleus in which a gamma ray is emitted.

The ejection of ions from the surface of a substance or medium into the surrounding space, because of the influence of an electric field or heat.

1. The emission of electrons or ions by substances that are highly heated, the charged particles being called thermions.
2. The discharge of electrons or ions from a solid or liquid as a result of its thermal energy.
3. The release of electrons when a material is heated; for example, electron emission when the tungsten cathode filament of a radiographic tube is heated to incandescence (emission of light by an object as a result of its being heated to a high temperature) by means of its low-voltage heating circuit.