Of Odin — who gave an eye at Mimir's well for a drink of memory and wisdom. A named power in this house's pantheon, and the reason the well has that name.
Old Norse Óðinn, from Proto-Germanic *Wodanaz, related to óðr (fury, inspiration, poetic frenzy); the god whose name is itself a word for possessed inspiration, who traded an eye at the well for wisdom.
The name behind Mimir's Well: the god who paid an eye for wisdom, and the reason the house's memory keeps that name rather than a plainer one.