A coined word meaning Light Amplification by Stimulated Emission of Radiation. A laser changes incoherent light, light whose vibrations do not have any consistent phase relationship, into coherent light, light whose vibrations are all in phase.

The light beam from a laser is highly concentrated, very narrow, and has an extremely high intensity. High-power lasers produce a great deal of heat in an extremely small area, and laser technology is opening new doors in all aspects of science.