Egeria was a nymph attributed a legendary role in the early history of Rome as a divine consort and counselor of Numa Pompilius, the second king of Rome, to whom she imparted laws and rituals pertaining to ancient Roman religion. Her name is used as an eponym for a female advisor or counselor.

A nymph is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature, are typically tied to a specific place or landform, and are usually depicted as maidens. They were immortal like other goddesses, except for the Hamadryads, whose lives were bound to a specific tree.