*laser disk*

n. A digital data storage medium consisting of a thin disk onto which the data is impressed by a laser, in the form of a linear sequence of dots; same as optical disk. The data is subsequently read back by the use of a laser beam. See also compact disk. The original disk may be created by use of a laser, but copies of the original disk may be created by a replicating process which does not itself require a laser. [ PJC ]