Seriously, that's the new spelling. I had written a post on the meaning long time back, but I was not expecting a double i stunt with Rajini sir's movie too. Looks like Superstition is going places these days.
Anyway, Kochadaiyan Ranadhiran was a Pandya king in the seventh century, who is known to have fought and won many battles against the Cheras, Cholas and Marathas among others.
But then, Kochadaiyan literally means 'a King with matted hair' as Ko means a King and Chadaiyaan means one with matted hair. So kochadaiyaan would be king with matted hair.
And then, with that name, Kochadaiyaan is also used for Lord Shiva sometimes.
And that's the name of Rajini sir's film. Kochadaiyaan. Or Kochadaiiyaan now.