disk seems to be serving multiple purposes currently, with existing tags for most cases.
As a floppy disk: post #678653
As a record: post #626044, post #950065
As a cd: post #374433
As a series of concentric circles, mimicking the appearance of a cd: post #467233, post #427762, post #431785
As disc a character from needless: post #680885
There are a lot of different ways someone could mistag this, so an alias wouldn't necessarily be the best solution. Perhaps making it ambiguous?
Another, and possibly more complete, solution would be to migrate disc to disk and make all the above cases, with exception to the chartag, imply disc. Then use disc as "any object or design that forms a thin perfect circle"
Updated by Aristocrat