Disk vs. Disc
Cambridge uses “disk” for information-storage devices and also records regional variation for general circular-object, media, and body senses, where “disc” is common and often mainly UK while US “disk” also occurs.
Use the spelling tied to the sense and domain: “disk” is standard for many data-storage uses, while “disc” is common for compact discs and many general round-object senses, with regional variation.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| computer storage or a hard-drive term is meant | disk | Use “disk” in established computing compounds such as “hard disk.” |
| a compact disc or other established optical-media term is meant | disc | Preserve the conventional “disc” spelling in terms such as “compact disc.” |
| a general round, flat object is meant | check the established term and regional/domain convention | The spellings overlap in some senses, so do not reduce the pair to one blanket regional rule. |
Quick tests
Meaning / construction test
Is the word part of an established computing or optical-media term?
If yes: Use the conventional spelling for that domain: for example, “hard disk” or “compact disc.”
If no: For a general round-object sense, check the term and house/regional convention instead of applying a computing rule.
Caveat: “Disk” and “disc” overlap in some general senses and can vary by domain or region. Preserve established technical compounds, product terminology, and house style.
Examples
The backup is stored on the hard disk.
“Hard disk” uses the established computing spelling.
The album was released on compact disc.
“Compact disc” uses the established optical-media spelling.
Insert the disc before starting playback.
The sentence refers to an optical disc rather than a computing disk.
Further guidance
Core difference
This pair mixes domain convention with regional variation; it is not accurately reduced to “disk = US, disc = UK” in every context.
Fast Test
Identify the intended sense first, then apply the documented regional or domain spelling for that sense.
Variant Boundary
Keep established technical compounds and official product terminology as written, and check the specific sense before changing spelling.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Disk — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Disk entry covering information-storage devices and US disk variation for general circular-object senses
- Disc — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Disc entry documenting mainly UK disc for round objects plus media/body senses with US disk variation