In reply to J Whittaker:
There's no official definition - and there never will be. And - for my part - who cares?: unless you're trying to make money (or a living) out of it, all this is a purely personal matter.
However, if want to find out, then - without knowing what your own experiences are - you could try solo alpine climbing at your technical limits. If you get away with it, I can guarantee you'll come away with powerful memories.
(The usual disclaimers apply.)
Post edited at 21:12