Casey's Tumblelog

I always thought of things this way, but now I feel vindicated. It also pleases the geek in me that Apple has a knowledge base article just for this. This may even eclipse my previous favorite KB article.

So, once and for all:

A disc refers to optical media, such as an audio CD, CD-ROM, DVD-ROM, DVD-RAM, or DVD-Video disc. […] All discs are removable, meaning when you unmount or eject the disc from your desktop or Finder, it physically comes out of your computer.

However:

A disk refers to magnetic media, such as a floppy disk, the disk in your computer’s hard drive, an external hard drive. […] Disks are usually sealed inside a metal or plastic casing (often, a disk and its enclosing mechanism are collectively known as a “hard drive”).

Link via @bjango