You might say you’re the boss man in your household, but if everybody else in the family ignores you, 'boss man' is probably a titular position for you. In other words, it’s just a title. There’s no power behind it.
We get titular from the Latin word titulus, meaning "title." Nowadays, it means that you hold an official title but don’t have any power or responsibility along with it. The Queen of England is a titular head of state. She doesn’t actually govern. A titular director doesn’t direct. Titular can also mean referencing the title. If you're playing the role of Dave in the play All About Dave, you're playing the titular role.