Pronunciation: (ap"u-rish'un),[key] —n. 1. a supernatural appearance of a person or thing, esp. a ghost; a specter or phantom; wraith: a ghostly apparition at midnight. 2. anything that appears, esp. something remarkable or startling: the surprising apparition of cowboys in New York City. 3. an act of appearing; manifestation.
4. Astron.the appearance or time when a comet, esp. a periodic one, is visible: the 1986 apparition of Halley's comet.