CD-RW means 'Compact Disc - Re-Writer' which basically means that it can take a blank CD and write information on it. It can also take CDs that have already been used (usually CDs that an individual has used, not a company making music CDs), and take all the information on it, and then put brand new information on it. It will also play any CD you put in it (usually) but cannot read, or write DVDs.