| illumination, Kohler | <microscopy> A method of microscopical illumination, first described by A. Kohler, in which an image of the source is focused in the lower focal plane of the condenser and the field diaphragm is focused in the specimen plane. (05 Aug 1998) |
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| illumination, oblique | <microscopy> Illumination from light inclined at an oblique angle to the optical axis. (05 Aug 1998) |
| illuminator | 1. One whose occupation is to adorn books, especially manuscripts, with miniatures, borders, etc. See Illuminate. 2. A condenser or reflector of light in optical apparatus; also, an illuminant. Origin: L, an enlightener, LL. Also, an illuminator of books. Source: Websters Dictionary (01 Mar 1998) |
| illuminism | A psychotic state of exaltation in which one has delusions and hallucinations of communion with supernatural or exalted beings. (05 Mar 2000) |
| illusion | 1. <psychology> An unreal image presented to the bodily or mental vision; a deceptive appearance; a false show; mockery; hallucination. "To cheat the eye with blear illusions." (Milton) 2. Hence: Anything agreeably fascinating and charning; enchantment; witchery; glamour. "Ye soft illusions, dear deceits, arise!" (Pope) 3. <physiology> A sensation originated by some external object, but so modified as in any way to lead to an erroneous perception; as when the rolling of a wagon is mistaken for thunder. Some modern writers distinguish between an illusion and hallucination, regarding the former as originating with some external object, and the latter as having no objective occasion whatever. Illusion refers particularly to errors of the sense, delusion to false hopes or deceptions of the mind. An optical deception is an illusion, a false opinion is a delusion. Synonym: Delusion, mockery, deception, chimera, fallacy. Origin: F. Illusion, L. Illusio, fr. Illudere, illusum, to illude. Source: Websters Dictionary (01 Mar 1998) |
| illusion of doubles | <syndrome> The delusional belief that a person (or persons) close to the schizophrenic patient has been substituted for by one or more impostors; may have an organic aetiology. Synonym: Capgras' phenomenon, illusion of doubles. (05 Mar 2000) |
| illusion of movement | Successive stimulation of neighboring retinal points which causes the sensation of movement. Oculogravic illusion, apparent movement of the visual field when the body is subjected to acceleration; due to gravity. Oculogyral illusion, an illusion occurring in angular acceleration in which the position of fixed light appears to drift. Optical illusion, a false interpretation of the colour, form, size, or movement of a visual sensation. (05 Mar 2000) |
| illusional | Relating to or of the nature of an illusion. (05 Mar 2000) |
| illusionist | One given to illusion; a visionary dreamer. Source: Websters Dictionary (01 Mar 1998) |
| illusions | The misinterpretation of a real external, sensory experience. (12 Dec 1998) |
| illustrate | 1. To make clear, bright, or luminous. "Here, when the moon illustrates all the sky." (Chapman) 2. To set in a clear light; to exhibit distinctly or conspicuously. "To prove him, and illustrate his high worth." (Milton) 3. To make clear, intelligible, or apprehensible; to elucidate, explain, or exemplify, as by means of figures, comparisons, and examples. 4. To adorn with pictures, as a book or a subject; to elucidate with pictures, as a history or a romance. 5. To give renown or honor to; to make illustrious; to glorify. "Matter to me of glory, whom their hate Illustrates." (Milton) Origin: L. Illustratus, p.p. Of illustrare to illustrate, fr. Illustris bright. See Illustrious. Source: Websters Dictionary (01 Mar 1998) |