A doppelgänger is the ghostlyin some cases, the physicaldouble
of a living person. The word "doppelgänger" is a loanword from
German, in which language it is written (as with any German noun)
with an initial capital letter: Doppelgänger. The word derives from
Doppel ("double") and Gänger ("goer").
In English, the word is conventionally uncapitalized. It is also
common to drop the German diacritic umlaut from the letter "ä,"
writing "doppelganger," although in German the correct spelling
without the umlaut would be "doppelgaenger."
In the vernacular, "Doppelgänger" has come to refer to any double
or look-alike of a personmost commonly an "evil twin"or to
bilocation.
The word is also used to describe a phenomenon whereby one catches
his own image out of the corner of his eye. In some traditions,
seeing one's own doppelgänger is an omen of death. A doppelgänger
seen by a person's friends or relatives may sometimes bring bad
luck, or indicate an approaching health problem.
