The Definition Of Ufo According Some Dictionary

OXFORD DICTIONARIEShttp://oxforddictionaries.com/view/entry/m en gb0893800#m en gb0893800UFO: a mysterious object seen in the sky for which it is claimed no orthodoxscientific explanation can be found, often supposed to be a vehicle carryingextraterrestrials

CAMBRIDGE DICTIONARY ONLINEhttp://dictionary.cambridge.org/dictionary/british/ufoUFO: abbreviation for unidentified flying object: an object seen in the skywhich is thought to be a spacecraft from another planet

LONGMAN ENGLISH DICTIONARY ONLINEhttp://www.ldoceonline.com/dictionary/UFOUFO: a strange object in the sky, that some people believe is a spaceshipfrom another world [= flying saucer]

WEBSTER'S ONLINE DICTIONARYUFO: An (apparently) flying object whose nature is unknown; especially thoseconsidered to have extraterrestrial origins.