• WordNet 3.6
    • n delusion the act of deluding; deception by creating illusory ideas
    • n delusion a mistaken or unfounded opinion or idea "he has delusions of competence","his dreams of vast wealth are a hallucination"
    • n delusion (psychology) an erroneous belief that is held in the face of evidence to the contrary
    • ***
Webster's Revised Unabridged Dictionary
    • Delusion That which is falsely or delusively believed or propagated; false belief; error in belief. "And fondly mourned the dear delusion gone."
    • Delusion The act of deluding; deception; a misleading of the mind.
    • Delusion The state of being deluded or misled.
    • ***
Century Dictionary and Cyclopedia
    • n delusion The act of deluding; a misleading of the mind; deception.
    • n delusion The state of being deluded; false impression or belief; error or mistake, especially of a fixed nature: as, his delusion was unconquerable. See the synonyms below.
    • n delusion Synonyms Illusion, Delusion, Hallucination. As now technically used, especially by the best authorities in medical jurisprudence, illusion signifies a false mental appearance or conception produced by an external cause acting through the senses, the falsity of which is capable of detection by the subject of it by examination or reasoning. Thus, a mirage, or the momentary belief that a reflection in a mirror is a real object, is an illusion. A delusion is a fixed false mental conception, occasioned by an external object acting upon the senses, but not capable of correction or removal by examination or reasoning. Thus, a fixed belief that an inanimate object is a living person, that all one's friends are conspiring against one, that all food offered is poisoned, and the like, are delusions. A hallucination is a false conception occasioned by internal condition without external cause or aid of the senses, such as imagining that one hears an external voice when there is no sound to suggest such an idea. If a person walking at twilight, seeing a post, should believe it to be a spy pursuing him, and should imagine he saw it move, this would be an illusion; a continuous belief that every person one sees is a spy pursuing one, if such as cannot be removed by evidence, is a delusion; a belief that one sees such spies pursuing, when there is no object in sight capable of suggesting such a thought, is a hallucination. Illusions are not necessarily indications of insanity; delusions and hallucinations, if fixed, are. In literary and popular use an illusion is an unreal appearance presented in any way to the bodily or the mental vision; it is often pleasing, harmless, or even useful. The word delusion expresses strongly the mental condition of the person who puts too great faith in an illusion or any other error: he “labors under a delusion.” A delusion is a mental error or deception, and may have regard to things actually existing, as well as to illusions. Delusions are ordinarily repulsive and discreditable, and may even be mischievous. We speak of the illusiom of fancy, hope, youth, and the like, but of the delusions of a fanatic or a lunatic. A hallucination is the product of an imagination disordered, perhaps beyond the bounds of sanity; a flighty or crazy notion or belief, generally of some degree of permanence; a special aberration of belief as to some specific point: the central suggestion in the word is that of the groundlessness of the belief or opinion.
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Chambers's Twentieth Century Dictionary
    • n Delusion de-lū′zhun the act of deluding: the state of being deluded: a false belief: error
    • ***


  • Benjamin Disraeli
    “The disappointment of manhood succeeds the delusion of youth.”
  • Ludwig Borne
    Ludwig Borne
    “Getting rid of a delusion makes us wiser than getting hold of a truth.”
  • Derek Jarman
    Derek Jarman
    “The preserve of ambition and folly in pursuit of illusion, or delusion.”
  • Christian Nevell Bovee
    “No man is happy without a delusion of some kind. Delusions are as necessary to our happiness as realities.”
  • Yasutani Roshi
    Yasutani Roshi
    “The fundamental delusion of humanity is to suppose that I am here and you are out there.”
  • Edmund Burke
    “The people never give up their liberties, but under some delusion.”


Webster's Revised Unabridged Dictionary
L. delusio, fr. deludere,. See Delude
Chambers's Twentieth Century Dictionary
See Delude.


In literature:

Let us not fall into the delusion of mistaking a local commotion for a revolution.
"The Victim" by Thomas Dixon
Several centuries ago visual delusion was with adults what it is now with children in remotest country parts.
"Life of St. Francis of Assisi" by Paul Sabatier
They concern (i) causality, (ii) time, (iii) space, and (iv) delusions.
"The Concept of Nature" by Alfred North Whitehead
The world, and India with it, is held in the grip of delusion.
"Caves of Terror" by Talbot Mundy
The motive may be to extort blackmail, revenge, or mere delusion.
"Aids to Forensic Medicine and Toxicology" by W. G. Aitchison Robertson
The hope is not a delusion, though its realization may be many years postponed.
"Thoughts on Educational Topics and Institutions" by George S. Boutwell
They were under no delusions on the subject.
"The Triumph of John Kars" by Ridgwell Cullum
No delusions could live in this land stripped of all conciliatory deception.
"The Emigrant Trail" by Geraldine Bonner
You are not answerable for my extravagant self-delusions.
"Sword and Gown" by George A. Lawrence
No delusions or hallucinations could be elicited.
"Studies in Forensic Psychiatry" by Bernard Glueck
Mr. Duncan had warned him against the delusion that man is entirely master of his destiny.
"The Cow Puncher" by Robert J. C. Stead
There seemed to be boundless liberty, and the delusion is complete when there is no sense of limitation.
"Confessions of Boyhood" by John Albee
Pre-natal culture and telegony were found to be mere delusions.
"Applied Eugenics" by Paul Popenoe and Roswell Hill Johnson
Delusions, certain popular, concerning diseases, 123-125.
"How to Live" by Irving Fisher and Eugene Fisk
The old Roman delusions and customs were as extraordinary as those of any nation with which history has made us acquainted.
"The Mysteries of All Nations" by James Grant
But bitterer far than this, than these, than all, is waking from our first delusion!
"The Young Duke" by Benjamin Disraeli
It is my intention to endeavor to show the origin of this delusion.
"Sophisms of the Protectionists" by Frederic Bastiat
In the examination of a patient with mental disease the physician looks for delusions, illusions, and hallucinations.
"The Necessity of Atheism" by Dr. D.M. Brooks
Fashions, fads, affectations, poses, ideals, manias, popular delusions, follies, and vices must be included in the mores.
"Folkways" by William Graham Sumner
The Prince de Carignan made enormous profits while the delusion lasted.
"Memoirs of Extraordinary Popular Delusions and the Madness of Crowds" by Charles Mackay

In poetry:

These the old gods hate,
Dwellers in dream-land,
Drinking delusion
Out of the empty
Skull of the Past.
"The Voyage To Vinland: Bioern's Beckoners" by James Russell Lowell
All my error, all my weakness,
All my vain delusions fled:
Hope again revived, and gladness
Waved its wings above my head.
"The Buried Flower" by William Edmondstoune Aytoun
Now the grave gives up its prey,
Friends arise, but swift away;
Dreams disperse, delusions fly,
And shew of sleep the mockery.
"Queen Mab And Her Fats" by Charlotte Dacre
Delusive grandeur never wreath'd
Around Contentment's head,
'Till war its flaming sword unsheath'd,
And wide destruction spread.
"The Complaint" by Thomas Gent
But ill shall the rootless virtue stand
Temptation's trying hour,
And soon shall the feeble spirit bend
To earth's delusive power.
"The Vine-Branch" by Caroline Fry
"Ah, dear, delusive, distant shore,
By dreams of futile fancy gilt!
The riverside we never saw,
The palm leaf hut was never built!
"Yasmini" by Laurence Hope

In news:

Delusion in Death Publisher: G.P.
Washington's European delusion in debt crisis.
Self- Delusion and the Cult of Militarism.
Reality TV Causes "Truman Show Delusion ".
Demography, Destiny, and Delusion .
The American Dream seems to have morphed into the American Delusion .
Author Michael Lewis On Wall St's Delusion .
Hope and delusion in health care.
Americans are outfoxed by the democracy delusion .
Live-blogging: 'The God Delusion .
Richard Dawkins, author of "The God Delusion ," is on Midmorning this morning.
China's Olympic Delusion The Nation.
Grannan's models pose as they desire to be seen, even if, as Gail once told the photographer, "All we really have are our delusions , dear.".
Yet with her well-sculpted, if weathered, starlet's mug, she has delusions of her own.
Adobe CS3 Details, Leopard Rumors, Ballmer's Self- Delusion , and More.

In science:

And there is a definite mismatch between the scientist’s drive to extend the reach of his or her methodology, and the widespread sense of an intrusion of algorithmic thinking into areas where it is not valid. A recent example is the controversy around Richard Dawkins’ book32 on The God Delusion.
Definability in the Real Universe
Contrary to this almost universal delusion the expression (2.12) is incorrect for description of harmonic emission by a single atom and the dipole momentum d(t) is not realvalued, both in the exact formulation (2.8) and within the approximation neglecting the continuum-continuum transitions (2.11).
Quantum theory of a high harmonic generation as a three-step process
Kant labored under the delusion of the CCP—the notion that the world’s synchronic multiplicity derives from surfaces that carve up space like three-dimensional cookie cutters,—as we all do, thanks to our neurophysiological make-up (see Sec. 9).
Quantum Mechanics and the Cookie Cutter Paradigm