An optical storage technology that stores and plays back data. "Read only" means the information on the disc may be capable of being displayed or used but not deleted. CD-ROMs are commonly used for encyclopedias, dictionaries, and software libraries, and they are also used for multimediaapplications. One CD-ROM can hold around 650 megabytes, or the equivalent of 700 floppy disks.
CD-ROMs have become a favorite medium for installing programs, since they cost only slightly more to manufacture than floppy disks and most major software applications would require at least five floppies. Most computers now have a CD-ROM drive. Don't sound hopelessly out of touch with technology-be sure to use the term "CD-ROM" to refer to the technology or the discs, but not to the hardware you play the discs on; that's a "CD-ROM drive."