titular (adj.)

c. 1300, "inscription, heading," from Old French title "title or chapter of a book; position; legal permit" (12c., Modern French titre, by dissimilation), and in part from Old English titul, both from Latin titulus "inscription, label, ticket, placard, heading; honorable appellation, title of honor," of unknown origin. Meaning "name of a book, play, etc." first recorded mid-14c. The sense of "name showing a person's rank" in English is first attested 1580s. Sports championship sense attested from 1913 (originally in lawn tennis), hence titlist (1913). A title role in theater is one which gives its name to the play.