What is a pirate?

I can not understand - explain to me what is a pirate? Some people tell me that downloaded and cracked license already pirates. I don't think so. Other people tell me that pirates, is as it should be raw part of the game that's not out yet. I think it is likely the latter.
But pirates are different. I tried to play pirates and license Grand Theft Auto 4 - they are very different. And there are games that do not differ.
More questions: And Repack it also pirates? Piratok why was so little when I remember in 2008, the Internet is teeming with them?
I hope there are people who will respond to at least one main my question.