In Arabic, the word أسطوانة originally means cylinder (etymology), so how come it can also mean disc?!
Answer
Because of the phonograph.
So the reason the word أسطوانة 'cylinder' came to mean disc as well is because of the evolution of phonographs. A phonograph cylinder was called أسطوانة, and when the phonograph record came out people kept calling it أسطوانة as well.
Obviously Arabic has a word for disk, it's قُرص. And formal/standard Arabic is not so keen on the idea that أسطوانة should be used as 'disk', but the cat has been out of the bag for too many decades, and now a CD is "أسطوانة cd" and the disc in a disc cutter or angle grinder is also "أسطوانة".
But a hard disk is not, because the rotating disk is not visible and so no one called it أسطوانة. Instead in colloquial it's called هارد hard and in standard Arabic and some dialects it's called "قُرص صَلب".
Has anyone encountered a similar case before?
