# projection

Pronunciation: US say "pruh-JEK-shuhn" /pɹəˈd͡ʒɛkʃən/; UK

## Noun

1. A forecast or estimate of a future value, reached by extending current trends or data.
   - Simple: A guess about future numbers, based on the way things are going now.
   - _The budget projection shows revenue climbing through the summer._
   - _Analysts based their projection on five years of sales data._
2. The showing of an image on a surface by a device such as a movie, video, overhead, or slide projector.
   - Simple: The showing of a picture or movie on a screen using a special light machine.
   - _The projection on the lecture screen was too dim for the back rows to read._
   - _Cinema projection moved from celluloid reels to digital files within a decade._
3. The assumption that others share one's own thoughts and feelings, including blaming others for faults that more truly belong to oneself.
   - Simple: Believing that others think and feel as you do, and blaming them for faults that are really yours.
   - _Her projection led her to assume her colleagues resented her, though no one did._
   - _Accusing others of selfishness can itself be a form of projection._
4. A part that protrudes or juts out from a surface or body.
   - Simple: A part of something that sticks out past the rest.
   - _A bony projection at the base of the skull anchors several neck muscles._
   - _The sculpture's sharp projection caught the light and threw a long shadow._
5. The act of throwing, propelling, or casting something forward.
   - Simple: The act of throwing or pushing something forward.
   - _The catapult's projection of the boulder cleared the castle wall._
   - _Good breath control improves the projection of a singer's voice._
6. A system of intersecting lines, with its supporting mathematics, used to represent the curved surface of the Earth on a flat map.
   - Simple: A way of drawing the round Earth on a flat map.
   - _The Mercator projection preserves angles but badly exaggerates area near the poles._
   - _Cartographers select a projection based on which properties they need to keep accurate._
7. An image of an object cast onto a surface of fewer dimensions, such as a three-dimensional form represented on a flat plane.
   - Simple: A flat picture of a solid shape, like its shadow on a wall.
   - _The projection of the sphere onto the plane appears as a flat disk._
   - _Engineers study the orthographic projection of a part to read its true dimensions._
8. The image that a translucent object casts onto another surface when light passes through it.
   - Simple: The picture that light makes when it shines through a see-through object onto another surface.
   - _The lampshade threw a warm projection onto the ceiling._
   - _Photographers used the projection of a backlit leaf to study its delicate veins._
9. A linear transformation that maps vectors onto a subspace and leaves them unchanged when applied a second time.
   - Simple: In math, an operation that drops points onto a smaller space, and doing it twice changes nothing more.
   - _The projection maps each vector onto its component within the chosen subspace._
   - _Because it is idempotent, the projection leaves vectors already in the subspace unchanged._
10. The distance from the skin over which a perfume's scent can be detected.
   - Simple: How far away you can smell a perfume on someone's skin.
   - _Reviewers praised the perfume's projection, which filled the room for hours._
   - _Warm skin tends to boost a fragrance's projection._
11. A transformation that extracts a fragment or component from a larger mathematical object.
   - Simple: In math, an operation that pulls out one piece of a bigger object.
   - _The projection returns the first coordinate of each ordered pair._
   - _Applying the projection strips away every component except the one selected._
12. In category theory, a morphism from a product object to one of its component objects.
   - Simple: In math, an arrow that takes a combined object and gives back one of its parts.
   - _The projection sends the product object to its first component._
   - _A categorical product is equipped with a projection onto each factor._
13. The preservation of a lexical item's properties as the phrase structure of a sentence is generated.
   - Simple: In grammar, the rule that a word keeps its features as a sentence is built up.
   - _Projection ensures that a verb's argument structure is reflected throughout the syntactic tree._
   - _Under projection, the properties of each word constrain the phrases built around it._

## Noun

14. A supposed process by which alchemists believed large quantities of base metals could be transmuted, as into gold or silver. *(obsolete)*
   - Simple: In old alchemy, a supposed way of turning large amounts of common metals into gold.
   - _He swore that a single grain of the stone, cast in projection, would ennoble a whole pound of mercury._
   - _The manuscript described the projection that promised to convert base metal into silver._
15. The critical, decisive stage reached in any process, especially one in cooking. *(archaic)*
   - Simple: The most important turning point in a process, especially in cooking.
   - _The sauce reached its projection just as the guests arrived, thickening to a perfect gloss._
   - _She judged the projection of the boiling syrup by its color and bubbles._

## Origin

Borrowed either from Middle French "projection" or directly from its source, the Classical Latin "prōiectiō" (stem "prōiectiōn-"), from "prōiciō"; equivalent to "project" plus "-ion". Compare Modern French "projection", German "Projektion", and Italian "proiezione".

Source: DictionaryAI, https://dictionaryai.com/define/projection (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).