For the most part, disc and disk can be used interchangeably to describe flat, round objects such as saucers or Frisbees. The British as a whole tend to prefer disc, while Americans generally use disk as their default spelling. Historically, the word disk entered the popular vernacular first, sometime during the 17th century. Many English words were formed from Germanic roots, which explains the use of a final hard K sound in words such as desk, whisk, task and disk.

Several centuries later, however, there was a movement towards incorporating Latin roots whenever possible. The Latin word discus, for example, was a more accurate predecessor for the newly-minted English word disc. The word disc was used to describe the flat, round recording medium used to play phonograph records. A person who played these musical discs for a living would be called a "disc jockey." The association between the "disc" and audio or video recording devices has continued to the present day.

The word disk, on the other hand, became associated with another form of magnetic storage. The computer industry uses the "disk" spelling as shorthand for "diskette." A round piece of magnetic recording material protected by a hard shell is known as a hard disk, and the device used to access it is a disk drive. It could be argued that a "disc" deals primarily with optical media, such as a compact disc or DVD, while a "disk" is more closely associated with magnetic storage, such as a computer's hard disk drive.

While there is nothing inherently wrong with either spelling, there are times when one is preferable to the other. A person may want to use the hard K "disk" when forming compound nouns, such as a "disk holder," in order to avoid an awkward soft C pronunciation by the reader. Some professions may prefer one spelling over another as well. A chiropractor may speak of a "herniated disc", while a mechanic may notice a worn "disk brake." The difference between a disc and a disk outside of the magnetic recording world may just be a matter of personal or cultural preference.