πρωταγωνιστής

English (LSJ)

οῦ, ὁ, on the stage,

   A one who plays the first part, chief actor, ib.816f; π. τοῦ δράματος Luc.Cal.7: metaph., [ὁ Αἰσχύλος] τὸν λόγον π. παρεσκεύασεν Arist. Po.1449a18: generally, leader, π. τῆς ὑπηρεσίας Clearch.25; τοῖς μαθηματικοῖς, of king Antiochus, Ps.-Diocl. ap. Paul.Aeg.1.100: expl. of πρόμαχος, EM612.51.