illusion

ih-LOO-zhun /ɪˈluːʒn/
nounB2IELTSTOEFLGRESAT
generalacademic

A false perception or interpretation of real sensory information; a deceptive appearance.

Unlike a hallucination (perceiving something with no physical source), an illusion misinterprets real physical stimulus.

The story behind the word. From Latin 'illusiō' (a mocking or trickery), from 'illudere' (to mock or play with), composed of 'in-' (upon) + 'ludere' (to play). When you experience an illusion, your eyes or senses are 'playing games' with you.

Word relationships

  • misconception: 'Misconception' is an error in thought or idea, while 'illusion' usually stems from distorted sensory perception.
  • hallucination: A 'hallucination' is perceiving something with zero physical stimulus; an 'illusion' distorts a real physical stimulus.
  • reality: 'Reality' refers to actual physical existence and truth.
  • truth: 'Truth' refers to factual correctness.

Commonly confused with

  • allusion: An 'allusion' is an indirect reference to literature/history; an 'illusion' is a false sensory perception.
  • delusion: A 'delusion' is a false cognitive belief; an 'illusion' is a distorted sensory perception.

Word family

  • illusory (adjective): Based on or producing an illusion; deceptive.
  • illusive (adjective): Deceptive or misleading.

Collocations

  • optical illusion
  • sensory illusion
  • shatter an illusion
  • create an illusion

Idioms & expressions

  • under the illusion

Example sentences

  • "The Muller-Lyer illusion tricks the brain into perceiving two lines of equal length as unequal because of angled arrowheads at their ends." Visual perception
  • "The world is all an illusion, but it is a very persistent one." Literature

Memory hook

ILLUSION comes from LUDERE (play). Your mind is PLAYING tricks on you. Senses playing tricks = ILLUSION.

When not to use

Do not confuse with 'delusion' (a false belief held despite proof, such as delusions of grandeur).

Fun facts

  • The famous 'rubber hand illusion' tricks your brain into feeling touch on an artificial rubber hand placed on a table while your real hand is hidden!
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