illusion

n. delusion, false impression of reality; misconception, false idea

An illusion is a distortion of a sensory perception, revealing how the brain normally organizes and interprets sensory stimulation. While illusions distort reality, they are generally shared by most people. Illusions may occur with more of the human senses than vision, but visual illusions, optical illusions, are the most well known and understood. The emphasis on visual illusions occurs because vision often dominates the other senses. For example, individuals watching a ventriloquist will perceive the voice is coming from the dummy since they are able to see the dummy mouth the words. Some illusions are based on general assumptions the brain makes during perception. These assumptions are made using organizational principles, like Gestalt, an individual's ability of depth perception and motion perception, and perceptual constancy. Other illusions occur because of biological sensory structures within the human body or conditions outside of the body within one’s physical environment.
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Illusion /il·lu·sion/ a mental impression derived from misinterpretation of an actual experience.illu´sional il·lu·sion n. 1. [more]Illusion - Community and Resources

Noun
1. an erroneous mental representation
(synonym) semblance
(hypernym) appearance
(hyponym) apparition, phantom, phantasm, phantasma, shadow
2. something many people believe that is false; "they have the illusion that I am very wealthy"
(synonym) fantasy, phantasy, fancy
(hypernym) misconception
(hyponym) bubble
3. the act of deluding; deception by creating illusory ideas
(synonym) delusion, head game
(hypernym) deception, deceit, dissembling, dissimulation
4. an illusory feat; considered magical by naive observers
(synonym) magic trick, conjuring trick, trick, magic, legerdemain, conjuration, deception
(hypernym) performance
(hyponym) card trick

n. illusion, delusion, false impression of reality; mirage, trick of eyesight