Compact disc
Compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony and released in 1982. The format was originally developed to store and play only sound recordings (CD-DA) but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. The first commercially available audio CD player, the Sony CDP-101, was released October 1982 in Japan.
CD single
A CD single (sometimes abbreviated to CDS) is a music single in the form of a compact disc. The standard in the Red Book for the term "CD single" is an 8cm (3 inch) CD (or Mini CD). It now refers to any single recorded onto a CD of any size, particularly the CD5, or 5-inch CD single. The format was introduced in the mid-1980s but did not gain its place in the market until the early 1990s. With the rise in digital downloads in the early 2010s, sales of CD singles have decreased.