CD-R stands for Compact Disc - Rewritable. It is re-writable CD media that is suitable for data CD compilations (CD-ROM). Though a CD-RW disc can be erased and written again, many CD players and other equipment generally perform better with CD-R media (always check if a CD player supports CD-RW before you buy it). A standard CD-RW is 120 mm in diameter and usually comes with a capacity of either 640MB or 700MB. A CD-RW will store 74 or 80 minutes of CD audio, but as mentioned, is much less compatible with CD players than CD-R.
Using software solutions such as Nero Burning Rom, at-home users can create audio CD or CD-ROM data CD compilations.