Short for Compact Disk-Recordable drive, a type of disk drive that can create CD-ROMs and audio CDs. This allows users to "master" a CD-ROM or audio CD for publishing. Until recently, CD-R drives were quite expensive, but prices have dropped dramatically.
A feature of many CD-R drives, called multisession recording, enables you to keep adding data to a CD-ROM over time. This is extremely important if you want to use the CD-R drive to create backup CD-ROMs.
To create CD-ROMs and audio CDs, you'll need not only a CD-R drive, but also a CD-R software package. Often, it is the software package, not the drive itself, that determines how easy or difficult it is to create CD-ROMs.
CD-R drives can also read CD-ROMs and play audio CDs.