I thought that a disc was a disc, and it is sometimes spelled disk. I now have got an indication that those two are not the same thing.

In this answer on Graphic Design, I wrote floppy disc in the answer.

I got a comment from someone that it should be floppy disk. He stated that

Disk is a magnetic storage media, while disc is an optical one.

Is this correct?

  • Interesting, but this is rapidly trending towards "only of historical interest", as solid state media pushes them towards obsolescence. Floppys are already pretty much in that category... – MickeyfAgain_BeforeExitOfSO Jan 11 '11 at 14:40
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    But hard-disks are still common, which is also a magnetic storage media. I used floppy as example, because that was what was commented on in the referenced post. – awe Jan 11 '11 at 15:12
  • @mickeyf: I think that as part of a treatise on the etymology of the words "Disk" and "Disc" this question still has merit. Although the technology is obsolete, people continue to use the word disk. – Andy F Jan 11 '11 at 15:28
  • @mickeyf what do you mean with "them"? And do you have any figures for that claim? SSDs are still waaay more expensive than good old HDs. Of course, flash memories are or have replaced floppies completely (not hard to do, actually), that's true. – Jürgen A. Erhard Jan 11 '11 at 15:56
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    After Edison invented the phonograph, some recordings were on cylinders, then recordings were on disks. Now disc with a c was often seen for phonograph recordings. A complete list of a recording artist's work was called a "discography". I guess my point is: the usage precedes both magnetic and optical recording. – GEdgar Jul 29 '11 at 13:54

Yes, according to Wikipedia the dis-k version of the word has been used to refer to magnetic storage media since the 1950s when IBM (a US company) pioneered the first hard drive. Subsequently the advent of optical media from companies such as Philips (Who are Dutch and therefore used the European spelling) and Sony meant that the form dis-c was chosen.

Etymologically speaking both words are synonyms, with the only difference being that disc is more common in British English, whilst disk is more popular in American English.

Rhodri (see below) also notes that the persistence of the word disk (even in European usage) for a magnetic storage medium is in deference to its American roots at IBM.

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    Plus in this context DISC is also an acronym - Digital Information Storage Cassette which is one of the reasons why it is used this way (however I'm guessing someone out there will dispute this) and that it is apart from Disk to denote the difference between them. – RoguePlanetoid Jan 11 '11 at 14:26
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    @RoguePlanetoid: Are you sure that isn't just a backronym? – Mr. Shiny and New 安宇 Jan 11 '11 at 14:38
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    @RoguePlanetoid: I agree with Mr. Shiny and New that DISC is indeed a backronym, as the word Disc pre-dates the information of storage cassettes by several centuries. Nice use though - I wasn't aware of it as an acronym. – Andy F Jan 11 '11 at 14:47
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    Anyone (@RoguePlanetoid?) have a link to this DISC acronym? Google comes up... with but one hit, and that's this thread :D – Jürgen A. Erhard Jan 11 '11 at 15:58
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    @Rhodri: I was about to post the same thing (about Philips/European spelling). Another likely influence is that the CD was a successor of the Laserdisc, which was most likely spelt with a "c" because it was originally called "Discovision", a name belying its 1970s roots :-) – psmears Jan 11 '11 at 20:21

I was on the ANSI committee that defined the 5 1/4 inch floppy specification (ANSI X3-B8) back around 1980. Even then, among all the existing manufacturers, there was no consensus about disk versus disc versus diskette.

So both "disk" and "disc" are correct.

As an aside, that was a pretty rockin' crew. That ANSI committee met three times a year, and always in some cool place, like Lake Tahoe, or New Orleans during Mardi Gras, so we could meet hard all day and party all night, entertaining each other on company expense accounts.

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    Where else but on a StackExchange site could you have access to information like that? :) – Jedidja May 13 '11 at 16:09
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    @Jedidja - it also explains why agreeing the ANSI C standard was much quicker than the ISO C11 standard - beer! – mgb Oct 17 '11 at 15:26

I believe that disk is American English whilst disc is English English. In the era of personal computers with removable disks, the spelling mostly came from the US computer industry and has taken hold in other parts of the Anglosphere.

Currently, most optical discs are popularly referred to as CDs, DVDs or Blu-Rays, so perhaps the distinction is moot.

No one has used a floppy-disk for decades, the 8-inch ones were certainly floppy, the 5.25 inch ones much less so and arguably didn't deserve the name. You might have been referring to a 3.5 inch diskette.

Athletes still throw a discus I think. Whether your car is equipped with disc-brakes or disk-brakes probably depends on where you purchased it.

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    -1 because technically Andy F's answer is correct, it's more than just a problem of which "English". Also -1 because floppy disks were called floppy because of the medium inside not the outer shell, which is why even 3.5 inch disks/diskettes were still called floppies: The inner medium indeed lacked rigidity even though the outer shell was hard plastic. – Josh Jan 13 '11 at 14:27
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    "stiffy - (University of Lowell, Massachusetts) A 3.5-inch microfloppy, so called because their jackets are more rigid than those of the 5.25-inch and the (obsolete) 8-inch floppy disk." (encyclopedia2.thefreedictionary.com/stiffies) "It was called a floppy because the first varieties were housed in bendable jackets" (encyclopedia2.thefreedictionary.com/floppy+disk) – RedGrittyBrick Jan 13 '11 at 16:15
  • @RedGrittyBrick: You are probably right, but the 3.5-inch are still called "floppy" because it's a cool name, and it's no need for a new name for it just because it's not that floppy anymore. And "stiffy" might give unwanted assosiations to other things... – awe Nov 1 '11 at 13:18
  • So, there's no 'disc' alternative to the word 'diskette'? Is 'diskette' used in British English? – Ask About Monica Apr 12 '13 at 17:25
  • @kbelder: I don't recall it ever being used in conversation. It did appear in writing in IBM manuals and similar places but in my IT career, In the era of 5 1/4" discs people mostly said "a floppy disc" or just "a floppy". As 3.5" discs became popular, people tended to say the whole phrase "a three and half inch disc" until they became predominant. Nowadays nobody I know really uses them, so the terms are rarely heard. – RedGrittyBrick Apr 12 '13 at 17:56

Well, he is right in the manner that this is how the different spellings have come to be used.

There is however no inherent difference between the spellings. The difference in usage between magnetic media and optical media is just a convention based on what was originally used when the media was introduced. When first hard disks were sold, the k spelling was chosen, but when the compact disc was introduced the c spelling was chosen.

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    But it is a convention that should be followed, regardless of the origin being a coincidence of who introduced the technologies, right? – awe Jan 11 '11 at 10:34
  • @awe could the distinction have arisen as a result of the work of a spelling reformer like Noah Webster? Anyone adhering to his principles might disagree with you, as might anyone keen on preserving traces of the (presumably Latin) origins of the word. The more timid amongst us should sheepishly follow the conventions of the herd. – RedGrittyBrick Jan 11 '11 at 10:54
  • @RedGrittyBrick: The difference between the two spellings supposedly arose in the 1700s as part of an increase in people wanting to spell words based on their roots (in this case, the latin "Discus"). As Disk had already been introduced in the mid 1600s it's not out of the question to imagine that disk as an Americanism had already been adopted. – Andy F Jan 11 '11 at 13:56
  • As I noted elsewhere, the hard-surfaced storage medium was not always a "disk", even among US manufacturers. In fact, I suspect that more manufacturers used "disc" than "disk" but IBM was the 800 pound gorilla. – Hot Licks Sep 15 '15 at 12:24

I worked for many years at U.S. technology magazines; it may be of interest to readers to see the word-list entries for disc and disk that governed our house style for those words at two magazines that shared the same word list. Here they are, from an era before DVDs appeared on the scene:

disc use for CD-ROMs, audio CDs, and laser discs

disk for floppy disks, hard disks; don’t use diskette

As you can see, the split in spelling that we followed was based not on a general U.S. preference for disk over disc, but on two separable categories of components/media: magnetic/electronic and optical/electronic. I suspect that the split arose because our magazines had gravitated toward hard disk and floppy disk in the early days of personal computers as a U.S. English preference, but nevertheless adopted the conventional spelling compact disc for CDs when they emerged.

Note that this is essentially anecdotal information: I don't know how many other U.S. publishers adopted the same distinction, but my impression is that our house style was not unusual in its treatment of these words.

As for why CDs were designated as compact discs instead of compact disks, even in the United States, I believe that the impetus came from vinyl records, which were usually styled discs, rather than disks, when the term was applied to them at all. That spelling follows in the tradition of the words discophile (since 1940, according to Merriam-Webster's Eleventh Collegiate Dictionary) discotheque (anglicized since 1954, according to MW), disco (the short form of discotheque, since 1964), and disco (the verb associated with disco music, since 1979).


Disk is American spelling while disc in British spelling. No difference otherwise.


Since no answer has an image to illustrate the difference, I'll take this chance and hopefully having some reps:

enter image description here

  • I'm sorry, but the terms have both been used since discs/disks were 14 inches in diameter and weighed several hundred pounds. – Hot Licks Jan 12 '17 at 13:38

Disk is short for diskette, a disc carried in a housing.

Hence hard and floppy disks. but compact discs.

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