Also Coherent Light.  Radiation composed of wave trains vibrating in phase with each other. Simply expressed: parallel rays of light.

Divergent light rays rendered parallel by means of a lens or other device, allowing a sharp image of the object to be focused at the focal plane of the lens.

The process by which divergent rays (white, or natural, light) are converted into parallel rays (coherent light).

A laser operating at a continuous output for a period of time equal to or greater than (≥) 0.25 seconds.  Continuous Wave is abbreviated CW.

Any area where the occupancy or activity of those within its confines is subject to access control and/or supervision for the purpose of protection from laser radiation hazards.