Getheren is apparently an eponym, that is, a person who was the founder of a place or custom or discovery. Other examples include Romulus, the legendary founder of Rome, and Charles Darwin, the very real founder of Darwinism. Sometimes eponyms were created in order to explain how a city originated, as may be the case for Romulus. Ursula Le Guin was the daughter of two anthropologists and her fiction shows a deep awareness of anthropological and linguistic concepts. Evidently, Le Guin wanted to underscore the significance of this tale-within-a-tale by implicating that the planet Gethen was named for the legendary Getheren of Shath.