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 8 cm (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.