'Title role' definitions:

Definition of 'title role'

(from WordNet)
noun
The role of the character after whom the play is named [syn: title role, name part]

Definition of 'Title role'

From: GCIDE
  • Role \Role\, Role \R[^o]le\, n. [F. See Roll.] A part, or character, performed by an actor in a drama; hence, a part of function taken or assumed by any one; as, he has now taken the role of philanthropist. [1913 Webster]
  • Title role, the part, or character, which gives the title to a play, as the part of Hamlet in the play of that name. [1913 Webster]