CD is the acronym for compact disk, which is an optical disk used for storing digital data. CDs were originally designed solely for the storage and playback of sound data, but would later be used to store nearly any kind of data.
Audio CDs and CD players have been commercially available in the United States since 1982.
With the growth in popularity of online availability of music during recent years and the spread of portable media players, CDs are slowly losing ground. An online music store typically enables people to purchase only the songs they like, instead of an entire album that they usually get with a CD.
Unlike file sharing applications, online stores follow copyright laws and offer higher quality meta-data.
You’ll find bloggers talking about CDs at sites like depauw.edu.