The way tags have been traditionally used on other sites (including this meta) is to have a hyphen:
apple-ii for questions about the Apple II
apple-iigs for questions about the Apple IIgs
apple for questions about Apple, the company (not sure if on-topic)
This allows searching for tags in a clear manner, with wildcards. For example this search for [apple-*] looks for all apple products. If we used apple2, as suggested in another answer, the corresponding search would be for [apple*] which would include apple2 but also apples, appleton, etc.
See also status-completed, status-deferred, etc. for more examples on this standard.