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English definition of “illusion”

illusion

noun     /ɪˈluːʒən/
FALSE IDEA [C, U] an idea or belief that is not true: He had no illusions about his talents as a singer. We are not under any illusion - we know the work is dangerous.True, real, false, and unreal
DIFFERENT [C] something that is not really what it seems to be: There is a large mirror at one end to create the illusion of more space. → See also optical illusionTrue, real, false, and unreal
(Definition of illusion noun from the Cambridge Learner's Dictionary © Cambridge University Press)

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