optical disc

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A plastic-coated disk on which data, such as text, music, or video, is digitally stored as microscopic regions of varying reflectivity and is read by scanning the surface with a laser.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A modern data storage medium consisting of a flat disc read mechanically by illumination with laser light. Various formats include the Laserdisc, compact disc, DVD, and Blu-ray.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a disk coated with plastic that can store digital data as tiny pits etched in the surface; is read with a laser that scans the surface