In Greek mythology, Orseïs (; Ancient Greek: Ὀρσηΐς, derived from ὄρσω - orsô, "to rouse, stir, awaken, excite or arise") was the water-nymph (Naiad) of a spring in Thessalia, Greece, and the mythical ancestor of the Greeks.
In Greek mythology, Orseïs was a water nymph from Thessaly, Greece, who was the ancestor of the Greeks.