Medical Definition of illusion
1: a misleading image presented as a visual stimulus
2a: perception of something objectively existing in such a way as to cause misinterpretation of its actual nature; especially : optical illusion—compare delusion 2b: hallucination 1c: a pattern capable of reversible perspective
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Dictionary: Definition of "illusion" Thesaurus: All synonyms and antonyms for "illusion" Spanish Central: Translation of "illusion" Nglish: Translation of "illusion" for Spanish speakers Britannica English: Translation of "illusion" for Arabic speakers Britannica.com: Encyclopedia article about "illusion"
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