DVD-RW (DVD ReWritable): A rewritable DVD format, introduced by Pioneer, that is similar to DVD+RW, but its capability to work as a random access device is not as good as +RW. It has a read-write capacity of 4.7 GB.
DVD+RW (DVD ReWritable): Developed in cooperation by Hewlett-Packard, Mitsubishi Chemical, Philips, Ricoh, Sony and Yamaha, it is the only rewritable format that provides full, non-cartridge, compatibility with existing DVD-Video players and DVD-ROM drives for both real-time video recording and random data recording across PC and entertainment applications.