names of important title characters are different. they were picked to have specific meanings.
-vader was picked because it means father in dutch.
-yoda, if i recall means wise one in some language or another.
-hans last name is solo, because it identifies the type of rogue character he is.
other names dont specifically tell who the person is, as much as just give a vague impression of who the person is.
-darth MAUL. doesnt really mean anything. just meant to sound menacing.
-lando calrisian. doesnt mean anything, but meant to sound charismatic, because lando is charismatic.
there are two possibilities for why GL chose to name dooku darth tyrannus.
1. its just meant to sound scary. GL has done this with minor characters, such as lando and darth maul.
But I beleive GL had a little more in mind. do you think GL chose the name simply because it sounded mencacing? Hardly. that would imply a connection the scary dinosaur name, which is simply cheesy.
tyrannus means "soveriegn, or absolute, ruler. I think GL chose that name because that is what Dooku wants. He wants to rule the galaxy. But for different motives than Sidious. Dooku left the Jedi order because he disagreed with the Council's politics, most noteably thier doing whatever the Chancellor wanted. Its also rumored that Dooku dillusionally beleives he is the chosen one. This would add weight to GL giving him the name because he felt he had the right to rule the universe. He feels that he is the chosen one, and can bring balance to the force. but he must play Palpatine to do it, to become the absolute power in the galaxy. Dooku knows Palpatine is corrupt. He knows a more just leader is needed. He feels because he is the chosen one, he is the one to do it. This is not a stretch, in ESB, Vader wanted Luke to join him so they could bring peace and order to the galaxy. The chosen one brings order. Dooku is just mistaken in his aspirations. In the end, I beleive he realizes the error of his ways, and returns to the light side
Maul according to the Oxford English Dictionary means - "tear the flesh of, or claw."
Collins dictionary says:
1) to handle clumsily, paw (it was a clumsy death),
2) to batter or lacerate
3) a heavy two handed hammer.
And if I remember correctly, on the DVD, the internet documentaries, the first one there...
he had a lot of books to look stuff up