Disc vs. disk?

Disc” and “disk” are word variants that both describe a flat, circular object. Unless you’re discussing optical vs. magnetic media, the word disk is more common for American English, while disc is the standard spelling for British English.

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What is the difference between disc and disk?

When it comes to the English Language, there’s a lot of room for confusion. This is especially true for words like “disc” and “disk,” which carry different meanings in the tech industry. 

For instance, the spelling of “disk” references magnetic storage devices such as computer disks or floppy disks. Meanwhile, we use the word “disc” to describe optical discs, such as audio CDs, video discs (e.g., DVD or Blu Ray), and more.

British English vs. American English

Outside of data storage, the main difference between disk and disc involves location: 

  • Disc is the preferred spelling for British English
  • Disk is more common for American English

There are several exceptions to these rules, as well. Words like ‘optic disc,’ ‘brake disc,’ and ‘disc golf’ always spell disc with a “c” instead of a “k.” 

What is the definition of disk?

The word disk (also disc) contains several definitions as a noun or verb, but its overarching connotation involves any object that resembles a ‘thin, flat, circular object’ or ‘plate.’ With this definition in mind, it’s easy to see how the noun commonly references: 

  • An intervertebral disk. 
  • A phonograph or gramophone record.
  • A disk hard drive or floppy disk. 
  • Disk brake pads.
  • The suit of Pentacles within a tarot card deck. 
  • A center of a flower head that bears compact, tubular flowers.
  • A curricular grid within a phototypesetting machine.

As a verb, the word disk describes how one loosens soil with a plow or disk harrow (a circular, concave tool), or records with a phonograph record.

Tech lingo: disc vs. disk

One of the most common definitions of disk and disc involves computers and data storage. In this sense, the noun may reference an optical disc, magnetic disk (hard disk drive platter), or the data stored within optical or magnetic devices themselves. 

What is a disc?

The word disc is a techy term for “optical media,” which are discs read by a laser inside a computer. Examples of optical media include: 

  • CD-ROM
  • DVD-ROM
  • DVD-RAM
  • DVD-Video 
  • CD-R
  • DVD-R

The acronym of “ROM” stands for “Read-Only Memory,” while “RAM” stands for “Random Access Memory.” Discs names ending with an “-R” allow users to burn content or ‘write files,’ while discs ending with “-RW” or “-RAM” enable users to rewrite files multiple times. 

Since optical discs lack magnetic charges, they store data more securely, and they tend to last longer (about seven times more than disks). A key feature of discs is that they’re removable, so the only time they exist in the computer is when they’re mounted or inserted into a disc reader (e.g., vehicle CD player, boom box, computer insert). 

What is a disk?

The word disk references “magnetic media,” a type of rotating disk that stores data using magnetic and electrical signals. Examples of disks include:

  • Floppy disks
  • Computer hard drives
  • External hard drives

Although it’s easy to envision a floppy disk or external hard drive, what you’re looking at from the outside is not the actual disk. Disks are typically located inside a casing, and the case itself is called a “hard drive.” 

A disk is called a “hard disk drive platter” when coated with magnetic material (usually a cobalt-based alloy). Computer experts refer to the coating as “media” because the magnetic material physically stores the data. The actual disk (without coating) is called a “platter.” 

Depending on its size, hard drives typically contain more than one disk or platter, which can vary in individual size. PC systems also include hard drives with larger disks that can store more memory. So, the larger the drive, the bigger the storage (ideally, anyway). 

Why does English use disc and disk differently?

It seems like everyone has an opinion about why English speakers use disk and disc differently. But at the end of the day, all of the answers are in the timeline. Let’s take a look at the history of disc vs. disk to understand the word’s correct usage. 

Discovery origin

The word disc stems from Latin discus as a reference to “quoit, “a game where players throw a ring-shaped object toward an upright peg. But before Latin, the word discus originated from Greek diskos (noun) and dikein (verb), which means ‘to throw.’ 

Disc then appeared in Old French as disque to describe the flat, circular appearance of the sun and moon before reaching Early Modern English in the mid-17th century. The word disk appears later in the 19th-century through the advent of gramophones, where English speakers used “disk” as the standard spelling for audio recordings (e.i., records). 

Since then, the spelling of disk became an American English variant, while British English speakers preferred to use “disc.” But as we’ll come to see, national spelling preferences could not avoid the looming tech boom. 

The age of computers: disk vs. disc

The technological differences between disk and disc began in 1956 with the release of IBM’s first commercial Hard Disk Drive (note the “k”). Nearly thirty years later, Philips Electronics and Sony patented the compact disc, separating the spellings and functions of storage drives in the years to come. 

Modern use of disc vs. disk

Until this day, the spelling of “disk” is associated with magnetic media devices rather than optical media. In fact, the word “disk” is thought to be a contraction of “diskette” (aka, the floppy disk) for British English. But the differences in spelling are not limited to nations or computers, either. 

Within medical terminology, the word disc is relevant to ophthalmology, while orthopedic terminology uses disc and disk interchangeably. The realm of ‘disc sports’ also uses terms with the letter “c” instead of “k” (e.g., disc golf, flying disc). 

Current distinctions for disc vs. disk are found within The Associated Press Stylebook, The Chicago Manual of Style, and the BBC News Style Guide. All three style guides agree that the use of “disk” is reserved for computer storage devices and medical references (with the exception of BBC for medical terms). 

Meanwhile, the style guides state how the word disc is preferred for “optical and laser-based devices” and the word ‘disc brake.’ The main difference in style occurs with Chicago’s writing guide, which prefers to use disc for ‘disc harrow’ and, particularly, “where the object in question is circular and flat.”

When to use disc in a sentence?

Always use the word disc for British audiences, unless you’re writing about magnetic disks such as floppy disks or hard drives. American English also uses the spelling of disc for topics involving disc sports, brake systems, and the practice of ophthalmology. 

Sentence examples:

U.S. and U.K.: 

“The audio CD is in the disc tray.” 
“The patient has an abnormal optic disc.”
“Let’s throw discs with the dog.” 
“The car features rear and front disc brakes.” 
“He used to be a disc jockey.”
“We have developed a prototype of an optical disc drive.”

U.K. only: 

“Grandma is looking for a disc vinyl on Amazon.” 
“Mother has a herniated disc.” 
“The formation of ice discs is a natural phenomenon.”
“The pool is shaped like a disc.” 
Disc harrows leave the farmlands dusty.”

When to use disk in a sentence?

Always use the word disk for American audiences unless you’re writing about: 

  • Optical discs (e.g., CD-ROM, DVD-R, etc.
  • Ophthalmology terms such as “optic disc.” 
  • Disc sports 

Sentence examples:

U.S. & UK: 

“The alert says your disk space is limited to 6 Gigabytes.” 
“You can’t store the Oxford English Dictionary on your hard disk drive.” 
“Let’s save a copy of the report on a floppy disk.” 

U.S. only: 

“The farmers are out disking the fields.” 
“Ankylosing spondylitis can cause swelling between disks in the spine.”
“We have a phonograph but no disk record.” 
“She serves appetizers on a disk-shaped platter.” 

Additional reading: American vs. British English

Learning the difference between American and British English spellings is difficult, but The Word Counter is here to make the lesson simpler. If you want to learn more about tricky spelling differences, check out the following articles: 

Test Yourself!

Test how well you understand the difference between disk and disc with the following multiple-choice questions. 

  1. True or false: Americans prefer spelling disk as disc.
    a. True
    b. False
  2. The technological differences between disk and disc occurred when?
    a. 17th century
    b. 18th century
    c. 19th century
    d. 20th century
  3. ____________ use the word ____________ to reference a computer’s hard drive.
    a. Only British English speakers, disk
    b. Only American English speakers, disc
    c. All English speakers, disk
    d. Only British English speakers, disc
  4. Which of the following misuses disc or disk?
    a. Optical disk
    b. Hard disk drive
    c. Lumbar disk
    d. Optic disc
  5. From where did the word disc originate? 
    a. Latin discus
    b. Greek diskos
    c. Old French disque
    d. A and B

Answers

  1. B
  2. D
  3. C
  4. A
  5. B

Sources

  1. Christensson, Per. “Optical Media Definition.” Tech Terms, Sharpened Productions, 25 Feb 2008. 
  2. Christensson, Per. “ROM Definition.” TechTerms. Sharpened Productions, 2006. 
  3. Disc.” Lexico, Oxford University Press, 2020.
  4. Disc.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., 2020.
  5. Disk.” The American Heritage Dictionary of the English Language, 5th ed., Houghton Mifflin Harcourt Publishing Company, 2020. 
  6. Disk, disc.” The Associated Press Style Book, Associated Press, 2020. 
  7. Disc/disk.” BBC News style guide, BBC News, 2020. 
  8. Good usage versus common usage.” Glossary of Problematic Words and Phrases, The Chicago Manual of Style Online, 2020. 
  9. Magnetic media.” Cambridge Dictionary, Cambridge University Press, 2020.
  10. Scott Mueller. “Hard Disk Platters (Disks).” PC Hardware Library Volume I: Hard Drives, Alasir, 1998.
  11. Medical Dictionary of Health Terms: A-C.” Harvard Health Publishing, Harvard Medical School, Dec 2011. 
  12. What’s the difference between a “disc” and a “disk?Apple Support, Apple, n.d. 
  13. Words with more than one spelling.” Learning English, BBC, 2020.