Illustration of illusion
- a and b are equal in length
illusion
noun
il·lu·sion
i-ˈlü-zhən 
plural illusions
1
a(1)
: a misleading image presented to the vision : optical illusion
(2)
: something that deceives or misleads intellectually
b(1)
: perception of something objectively existing in such a way as to cause misinterpretation of its actual nature
(2)
(3)
: a pattern capable of reversible perspective
2
a(1)
: the state or fact of being intellectually deceived or misled : misapprehension
(2)
: an instance of such deception
b
obsolete
: the action of deceiving
3
: a fine plain transparent bobbinet or tulle usually made of silk and used for veils, trimmings, and dresses
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Allusion and Illusion
Allusion and illusion may share some portion of their ancestry (both words come in part from the Latin word ludere, meaning “to play”), and sound quite similar, but they are distinct words with very different meanings. An allusion is an indirect reference, whereas an illusion is something that is unreal or incorrect. Each of the nouns has a related verb form: allude “to refer indirectly to,” and illude (not a very common word), which may mean “to delude or deceive” or “to subject to an illusion.”
Examples of illusion in a Sentence
The video game is designed to give the illusion that you are in control of an airplane.
They used paint to create the illusion of metal.
She says that all progress is just an illusion.
Recent Examples on the Web
Call it pixie dust, projection, illusion, artifice — who really cares?
—
Teri Sforza, Oc Register, 11 July 2025
The illusion is caused by the moon being seen close to the horizon, where trees and buildings give the human brain context.
—Jamie Carter, Forbes.com, 11 July 2025
Some choose complacency — seduced by comfort and the illusion that someone else will do the hard work of changing things.
—F. Willis Johnson, Twin Cities, 10 July 2025
The moon will appear low in the night sky this week, giving it an unnaturally large appearance known as the moon illusion.
—Jenna Prestininzi, Freep.com, 9 July 2025
See All Example Sentences for illusion
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Teri Sforza, Oc Register, 11 July 2025
The illusion is caused by the moon being seen close to the horizon, where trees and buildings give the human brain context.
—Jamie Carter, Forbes.com, 11 July 2025
Some choose complacency — seduced by comfort and the illusion that someone else will do the hard work of changing things.
—F. Willis Johnson, Twin Cities, 10 July 2025
The moon will appear low in the night sky this week, giving it an unnaturally large appearance known as the moon illusion.
—Jenna Prestininzi, Freep.com, 9 July 2025
See All Example Sentences for illusion
Cite this Entry
“Illusion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/illusion. Accessed 18 Jul. 2025.
Copy CitationKids Definition
illusion
noun
il·lu·sion
il-ˈü-zhən
1
: a misleading image presented to the eye
2
: the state or fact of being led to accept as true something unreal or imagined
3
: a mistaken idea
Medical Definition
illusion
noun
il·lu·sion
il-ˈü-zhən
1
: a misleading image presented as a visual stimulus
2
a
: perception of something objectively existing in such a way as to cause misinterpretation of its actual nature
especially
: optical illusion compare delusion sense 2
c
: a pattern capable of reversible perspective
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