LASER

[noun] [C] - (a device which produces) a powerful beam of light that is a single pure colour and consists of light waves moving in exactly the same way as each otherLasers are used for cutting hard substances such as metal and for performing delicate surgical operations.Lasers are also used to read information from compact discs and bar codes.Laser treatment involves the surgeon destroying the cancerous cells with a laser beam instead of cutting them out with a knife.There were heavy civilian casualties when a laser-guided bomb missed its target.A laser disc is a disc which stores information in a form that can be obtained using a laser.Some movies are now available on laser disc as well as on video cassette.A laser printer is a computer printer which works by shining a laser beam at a tube covered with carbon powder. Powder that is hit by the laser loses its electrical charge and falls off the tube and the powder that is left forms the image to be printed.The quality and speed of laser printing are much greater than dot-matrix and bubble-jet systems.