The Spelling of Disc: Disc or Disk?

The terms 'disc' and 'disk' are both used to describe a generally thin and circular object. The k-spelling came into the English language in the middle of the 17th century, whilst the c-spelling was introduced in the 18th century, based on the Latin root word 'discus'. By the 20th century, the c-spelling was preferred in British English, whilst the k-spelling was more popular in American English.

In computing terms, the two spellings are used to describe two different type of storage media.

Disc

The term 'disc' was originally used to describe the flat, round recording medium used to play phonograph records. The term has continued to be associated with audio or video recording devices, when the Dutch company Philips, along with Sony, developed the compact disc medium, and it is now used to refer to optical media, such as audio CDs, CD-ROMs, DVD-ROMs, DVD-RAMs, and DVD-Video discs. Discs are always removable, meaning they can be ejected and physically taken out of the computer. Some discs are read-only (e.g. CD-ROM), others allow you to burn content to the disc once (e.g. CD-R), whilst others still can be rewritten over many times (e.g. CD-RW).

Disk

The spelling 'disk' has always been traditionally more popular in the US, and so when the American company IBM pioneered the first hard disk drive storage devices in the 1950's, the k-spelling was used. This has led to the term 'disk' being used to refer to magnetic storage devices, such as floppy disks, the disk in a computer's hard drive, or an external hard drive. Disks are typically sealed inside a plastic or metal sleeve or casing, and are always rewritable unless intentionally locked or write-protected.

In technology terms, disks usually reproduce data magnetically, whilst discs reproduce it optically with lasers.