An apparition or double of a living person.
In fiction and folklore, a doppelgänger (German, literally a “double goer”) (pronounced [ˈdɔpəlˌɡɛŋɐ] ( listen)) is a paranormal double of a living person.
It also describes the sensation of having glimpsed oneself in peripheral vision, in a position where there is no chance that it could have been a reflection.
Doppelgängers often are perceived as a sinister form of bilocation and are regarded by some to be harbingers of bad luck. In some traditions, a doppelgänger seen by a person’s friends or relatives portends illness or danger, while seeing one’s own doppelgänger is said to be an omen of death.
Recent scientific experimentation has duplicated several doppelgänger effects when electrical stimulation was applied to the left temporoparietal junction of the brain of a patient.
In the contemporary vernacular of some English speakers, the word may be found used simplistically to identify any look-alike of a person, without regard to the supernaturalness and fundamental doubling intended in the meaning of the word.