Also found in: Dictionary, Thesaurus, Medical, Financial, Acronyms, Idioms, Wikipedia.


1. the dark portions of a picture
2. Med a dark area on an X-ray film representing an opaque structure or part
3. (in Jungian psychology) the archetype that represents man's animal ancestors
4. Brit designating a member or members of the main opposition party in Parliament who would hold ministerial office if their party were in power
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005


A region of darkness caused by the presence of an opaque object interposed between such a region and a source of light. A shadow can be totally dark only in that part called the umbra, in which all parts of the source are screened off. With a point source, the entire shadow consists of an umbra, since there can be no region in which only part of the source is eclipsed. If the source has an appreciable extent, however, there exists a transition surrounding the umbra, called the penumbra, which is illuminated by only part of the source. Depending on what fraction of the source is exposed, the illumination in the penumbra varies from zero at the edge of the full shadow to the maximum where the entire source is exposed. The edge of the umbra is not perfectly sharp, even with an ideal point source, because of the wave character of light. See Diffraction

McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc.

What does it mean when you dream about a shadow?

A shadow may represent the hidden aspects of the self. The dreamer often does not accept these parts of his or her personality and they are projected upon others until the dreamer can accept them and incorporate them into his or her psyche.

What does it mean when you dream about a shadow?

In psychology, the shadow refers to the personality traits and tendencies that one has rejected in developing one’s self-image. One of the most influential formulations of the shadow was put forward by the famous Swiss psychiatrist Carl Jung. In Jung’s personality theory, the ego represents the individual’s sense of personal self. This sense of personal identity is purchased at the expense of certain tendencies (e.g., socially undesirable traits), however, which are rejected as “not-self.” According to Jung, these rejected traits come together as a kind of unconscious “counterego” that he termed the shadow.

Although suppressed from conscious awareness, the shadow continues to influence our behavior in powerful ways. In particular, we may become unduly anxious or irritated when in an environment or around a person that in some way reminds us of repressed aspects of our self. If a person has rejected his or her own sexual drive, for example, that person may feel irrational fear or anger around an overtly sexual individual. The shadow may appear as a person in one’s dreams, usually as an individual of the same sex. In Jungian therapy, the shadow is viewed as a potential source of characteristics to be integrated into the subject’s ego structure.

The Dream Encyclopedia, Second Edition © 2009 Visible Ink Press®. All rights reserved.


A region of darkness caused by the presence of an opaque object interposed between such a region and a source of light.
A region which some type of radiation, such as sound or x-rays, does not reach because of the presence of an object, which the radiation cannot penetrate, interposed between the region and the source of radiation.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


A syntax-directed compiler written by Barnett and Futrelle in 1962. It was the predecessor to SNOBOL(?)

[Sammet 1969, p. 448, 605].
This article is provided by FOLDOC - Free Online Dictionary of Computing (
References in classic literature ?
It was vexatious; but in the warm lands everything grows so quickly; and after the lapse of eight days he observed, to his great joy, that a new shadow came in the sunshine.
Do you not know your old shadow? You certainly thought I should never more return.
After thee, however, O Zarathustra, did I fly and hie longest; and though I hid myself from thee, I was nevertheless thy best shadow: wherever thou hast sat, there sat I also.
Thus spake the shadow, and Zarathustra's countenance lengthened at his words.
But too great was the distance and too deep the shadow of its under side for me to distinguish any movement as of animal life.
So I hastened onward beneath the great shadow. As I ad-vanced I could not but note the changing nature of the vegetation and the paling of its hues.
To them, I said, the truth would be literally nothing but the shadows of the images.
At first, when any of them is liberated and compelled suddenly to stand up and turn his neck round and walk and look towards the light, he will suffer sharp pains; the glare will distress him, and he will be unable to see the realities of which in his former state he had seen the shadows; and then conceive some one saying to him, that what he saw before was an illusion, but that now, when he is approaching nearer to being and his eye is turned towards more real existence, he has a clearer vision, -what will be his reply?
To all appearances I had been shorn of a finger; nor could I get any visual impression of it till I extended it under the skylight and saw its shadow plainly blotted on the floor.
"Of course," I continued, "you cannot escape your shadow, but that was to be expected.
The blond cornfields were red gold, the haystacks turned rosy and threw long shadows. The whole prairie was like the bush that burned with fire and was not consumed.
Now, which of the multitude of faces that showed themselves before him was the true face of the buried person, the shadows of the night did not indicate; but they were all the faces of a man of five-and- forty by years, and they differed principally in the passions they expressed, and in the ghastliness of their worn and wasted state.