Yes, despite its use in the titles of most of the films of the series, the "Pink Panther" is not the Clouseau character, but a large and valuable fictitious diamond of the same name which is the "MacGuffin" of the first film in the series. The phrase reappears in the title of the fourth film, The Return of the Pink Panther, in which the theft of the diamond is again the center of the plot.