disk

Usage Have you ever noticed that when you buy a music CD, it is a compact disc, but when you buy a CD in a computer store it is usually a compact disk? Sometimes spelling varies according to how a word is used. Back in the late 19th century, when people were developing the technology for recording sound on a flat plate (what later became the vinyl phonograph record), the inventors referred to the plates as discs, using an alternate spelling of disk. The c spelling eventually became prevalent in the music industry, known for its disc jockeys. When American computer scientists developed flat storage devices back in the 1940s, they chose the common American spelling disk, and this is why we have hard disks installed on our computers. When the storage device known as the compact disk was invented, people in the music industry saw them as shiny substitutes for phonograph records, and they referred to them as compact discs, despite the fact that these same discs were compact disks when they stored nonmusical data. One of the advantages of abbreviations like CD is that they make spelling much simpler!