An illusion is something that looks or seems different from what it really is, often tricking your senses or mind. It can also mean a false idea or belief.
From Latin "illusio" meaning "mockery, deception," from "illudere" (to mock, to play with), built from "in-" (at) and "ludere" (to play). Over time, the word softened from deliberate trickery to any misleading appearance.
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