What determines a czar?

[SimpleName]

There is so much talk about czars, but I don't really understand how people determine somebody is a czar. There is no official czar positions of course, just advisory jobs (at least that I know of). So how do people conclude someone is necessarily a "czar" and not just a regular adviser? Or am I way off the mark?

[pcosmar]

–noun
1. an emperor or king.
2. (often initial capital letter) the former emperor of Russia.
3. an autocratic ruler or leader.
4. any person exercising great authority or power in a particular field: a czar of industry.


Hmmm.:(