A compact disc write-once or CD-R is a type of optical disc that can record data only once. It is a reliable storage medium mainly used for archiving data or distributing software. CD-Rs come in different forms and use various recording technologies. Some of the common synonyms for CD-R are recordable CD, write-compatible CD, CD-RW, WORM (Write Once Read Many), and Azo CD-R. The CD-RW is a rewriteable type of CD that can record data multiple times, while the Azo CD-R uses a unique dye technology that makes it more durable and resistant to UV rays. All in all, CD-Rs remain a popular choice for storing and distributing data.