Okay, okay, we'll go into this six-letter title a little more.
Batman was an attempt to rebrand the character of Batman for a new generation. Formerly a campy TV show with visible POWs, ZAPs, and BIFFs, Tim Burton and executive producer Michael Uslan sought to bring the character away from the purple tights and to its comic-boots, which were being darkened even more in the 1980's by comic writers Alan Moore and Frank Miller.
To do this, they needed the title to be simple. Not a "new" Batman or Batman the "next generation." No, by calling it simply "Batman" and making the poster the basic black-and-yellow bat-logo, they said to audiences that this is the definitive Batman.