Strymon, a proper name applied in Greek mythology to various persons: 1. A son of Mars and Helice, whose daughter Terina was also beloved by Mars and bore him Thrassa. 2. A son of Oceanus and Tethys, or of Pontus and Thalassa. The navigable river over which Strymon ruled was rendered unnavigable by Hercules; who drove through it the herds of Geryon.