Yes, soter is Gk for 'savior', while we're more familiar with the Latin salvator (as in El Salvador / San Salvador in Spanish). Soter is the 'S' in the Jesus fish acronym sign you see on the bumpers of some cars: Iesous CHristos THeou hUios Soter = ichthus. I first ran across soteriology when reading a huge book on early Christian heresies by some German Lutheran theologian historian. Lots of fun with Pelagianists, Arians, Donatists, Marcellianists, Priscillianists, et al.