projection

Etymology

From either the Middle French projection or its etymon, the Classical Latin prōiectiō (stem: prōiectiōn-), from prōiciō. Compare the Modern French projection, the German Projektion, and the Italian proiezione.

noun

1. Something which projects, protrudes, juts out, sticks out, or stands out.
   The face of the cliff had many projections that were big enough for birds to nest on.
2. The action of projecting or throwing or propelling something.
3. (archaic) The crisis or decisive point of any process, especially a culinary process.
4. The display of an image by devices such as movie projector, video projector, overhead projector or slide projector.
5. A forecast or prognosis obtained by extrapolation
6. (psychology) A belief or assumption that others have similar thoughts and experiences to one's own. This includes making accusations that would more fittingly apply to the accuser.
   Projection ia another mechanism of defense and is one that is utilized almost universally to explain one's minor mistakes, and in many cases the minor failures as well. By projection we place the blame for our acts upon others.... 1937, John W. Vann, “To What Extent Is Reality Adjustment Concerned In The Selection Of The Flying Trainee?”, in United States Naval Medical Bulletin, volume 35, page 437
   The morality of patriarchy, Mary Daly argues, is charactrized by "a failure to lay claim to that part of the psyche that is then projected onto 'the Other.'" 1980-05, Judith Plaskow, “Blaming Jews for Inventing Patriarchy”, in Lilith Magazine, volume 7
7. (photography) The image that a translucent object casts onto another object.
8. (cartography) Any of several systems of intersecting lines that allow the curved surface of the earth to be represented on a flat surface. The set of mathematics used to calculate coordinate positions.
9. (geometry) An image of an object on a surface of fewer dimensions.
10. (linear algebra) An idempotent linear transformation which maps vectors from a vector space onto a subspace.
11. (mathematics) A transformation which extracts a fragment of a mathematical object.
12. (category theory) A morphism from a categorical product to one of its (two) components.
13. (grammar) The preservation of the properties of lexical items while generating the phrase structure of a sentence. See Projection principle.
14. (alchemy, obsolete) A supposed mechanism for the transmutation of large quantities of base metals.
    I speak not here of Projection, whereby one part of an Aurifick Powder is said to turn I know not how many 100 or 1000 parts of an ignobler metal into silver or gold […] 1666, Robert Boyle, The Origine of Formes and Qualities[…], page 365
    But yet I would that every one should understand me aright, and not count me so simple, as if I did liken or compare my Aurum Potabile with that great Stone of the Philosophers, which transmutes vast quantities of imperfect metals into most pure Gold by projection […] 1689, Johann Rudolf Glauber, translated by Christopher Packe, The Works of the Highly Experienced and Famous Chymist, John Rudolph Glauber[…], page 216
    [Helmont] says, on another occasion, that an adept, after a few days of acquaintance, presented him with half a grain of the powder of projection, with which he transmuted nine ounces of quicksilver into pure gold. 1888, Arthur Edward Waite, Lives of Alchemystical Philosophers[…], page 167