Actual Owner
  
An Actual Owner is...the actual owner.
Bet you're shocked to read that, but as you might imagine, evil-do'ers often present themselves as being the actual or real owner, or beneficial owner, when in fact, they're just interlopers trying to abscond with a rube's hard-earned cash.
In partnerships and public companies, determining the actual owner doesn't necessarily involve evil-do'ers. Instead, there can be debate as to who controls the company, either via board member attribution, or share count behind the board.