I will have to re-do this picture soon. I now have a new “New Oxford Style Manual”, a new “Concise Oxford English Dictionary” and a new “AP Stylebook” AND my new “Chicago Manual of Style” should be arriving tomorrow. Time for a new photo then, I think.
Anyway, it’s Troublesome Pairs time and I had to check this one just in case the other day when I was doing a transcription – really, we don’t use these words very often now that computers don’t use floppy disks any more, and although vinyl records are a ‘thing’ again, they tend to be referred to as ‘vinyls’ rather than ‘discs’. Oops, I’ve given the game away already, haven’t I!
So, just to spell it all out for future reference …
A disc is a flat round thing (also used metaphorically, for example for the Sun, which is obviously really a sphere) and is the spelling used for the kind of disc that is a record. I think a disc only has to be flatter than it’s round to be a disc, because you get discs of cartilage in your spine which can slip.
A disk is the computer kind of item. It contains a disc on which data can be magnetically or optically stored (the latter including CD-ROMs).
And just to confuse, in the UK you can spell both with a k, and then you have to work out which it is from the context.
The talk of the first kind of disc got me thinking about cylinders. These have straight sides and an oval or circular cross-section, so in effect a disc is a kind of cylinder as long as it has some kind of three dimensional existence.