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English definition of “illusion”

illusion

noun [C]    /ɪˈlu·ʒən/
an idea or belief that is not true , or something that is not what it seems to be: We have no illusions about how difficult the job will be. [+ that clause] I was under the illusion that trains ran frequently on weekends (= I wrongly believed this). They managed to create the illusion of space in a tiny apartment . illusory    /ɪˈlu·sə·ri, -zə·ri/ adjective Her fears were illusory.
(Definition of illusion noun from the Cambridge Academic Content Dictionary © Cambridge University Press)
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