What is "prothoenor"

In Greek mythology, Prothoenor ( Greek: ) was one of the Greek leaders in the Trojan War, from Thespiae in Boeotia, son of Areilycus and Theobule, brother of Arcesilaus; he commanded eight ships. John Tzetzes makes him a son of Alector and Arteis, and thus a half-brother of Leitus and Clonius. According to the Iliad, he was killed by Polydamas, who immediately began to boast about it.