Projection, projections or projective may refer to:

Physics

Projection (physics) The vector projection of a vector on (or onto) a nonzero vector , sometimes denoted \operatorname_\mathbf \mathbf (also known as the vector component or vector resolution of in the direction of ), is the orthogonal projection of onto a straig ...

, the action/process of light, heat, or sound reflecting from a surface to another in a different direction * The display of images by a projector

Optics, graphics, and cartography

* Map projection, reducing the surface of a three-dimensional planet to a flat map * Graphical projection, the production of a two-dimensional image of a three-dimensional object

Chemistry

* Fischer projection, a two-dimensional representation of a three-dimensional organic molecule * Haworth projection, a way of writing a structural formula to represent the cyclic structure of monosaccharides * Natta projection, a way to depict molecules with complete stereochemistry in two dimensions in a skeletal formula * Newman projection, a visual representation of a chemical bond from front to back

Mathematics

* Projection (mathematics), any of several different types of geometrical mappings ** Projection (linear algebra), a linear transformation from a vector space to itself such that ** Projection (set theory), one of two closely related types of functions or operations in set theory **

Projection (measure theory) In measure theory, projection maps often appear when working with product (Cartessian) spaces: The product sigma-algebra of measurable spaces is defined to be the finest such that the projection mappings will be measurable. Sometimes for some re ...

, use of a projection map in measure theory **

3D projection A 3D projection (or graphical projection) is a design technique used to display a three-dimensional (3D) object on a two-dimensional (2D) surface. These projections rely on visual perspective and aspect analysis to project a complex object fo ...

, any method of mapping three-dimensional points to a two-dimensional plane ** Vector projection, orthogonal projection of a vector onto a straight line ** Projection (relational algebra), a type of unary operation in relational algebra * Projective geometry, the study of geometric properties that are invariant with respect to projective transformations *

Projective module In mathematics, particularly in algebra, the class of projective modules enlarges the class of free modules (that is, modules with basis vectors) over a ring, by keeping some of the main properties of free modules. Various equivalent characterizati ...

, a generalization of a free module * Projective object, a further generalization, in category theory * Projection method (fluid dynamics), means of numerically solving time-dependent incompressible fluid-flow problems

Biology

Projection areas Projection areas are areas in the four lobes (frontal, parietal, temporal, occipital) of the brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is ...

, areas of the brain where sensory processing occurs *

Projection fiber The projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. In human neuroanatomy, bundles of axons (nerve fibers) called tracts, within the brain, can be catego ...

, in neuroscience, white matter fibers that connect the cortex to the lower parts of the brain or the spinal cord

Linguistics

* Projection (linguistics), grammatical trait inheritance from a head to a phrasal category * Projection principle in syntax * Projection of

presupposition In the branch of linguistics known as pragmatics, a presupposition (or PSP) is an implicit assumption about the world or background belief relating to an utterance whose truth is taken for granted in discourse. Examples of presuppositions include ...

s in linguistics

Arts and entertainment

* "Projections" (''Star Trek: Voyager''), an episode of the television series ''Star Trek: Voyager'' * ''Projections'' (The Blues Project album), 1966 * ''Projections'' (John Handy album), 1968 * ''Projections'' (film), 2013 Croatian film

Other uses

Projection (alchemy) Projection was the ultimate goal of Western alchemy. Once the philosopher's stone or powder of projection had been created, the process of projection would be used to transmute a lesser substance into a higher form; often lead into gold. Typ ...

, process in Alchemy * ''Projections'' (journal), an interdisciplinary academic journal related to cinema and visual media *

Power projection Power projection (or force projection or strength projection), in international relations, is the capacity of a state to deploy and sustain forces outside its territory. The ability of a state to project its power into an area may serve as an e ...

, the capacity of a state to implement policy by means of force, or the threat thereof * Psychological projection, or "Freudian projection", a defense mechanism in which one attributes to others one's own unacceptable or unwanted attributes, thoughts, or emotions *

Social projection In social psychology, social projection is the psychological process through which an individual expects behaviors or attitudes of others to be similar to their own. Social projection occurs between individuals as well as across ingroup and outgr ...

, a cognitive bias that leads people to believe others are similar to themselves * Forecasting, making predictions of the future based on past and present data