Lis forLaser
A laser is a light source that either emits or converts emitted light to coherent light. This means that the light from the laser is all going in the one direction, with the light waves in synch.
Lasers have many, many uses in science and medicine. Less powerful lasers are also commonly used in laser pointers for pointing out words on a screen or whiteboard, and used to make light shows in nightclubs, as seen in the picture.