Dictionary
com'pact disk'
an optical disk approximately 4¾ in. (12 cm) in diameter, on which a program, data, music, etc., is digitally encoded for a laser beam to scan, decode, and transmit to a playback system, computer monitor, or television set.
Abbr.: CD Cf.
optical disk (def. 1).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.