projection

Projection (from Latin proicere "throw out, throw down") stands for:

Mathematics and Computer Science:

Projection (set theory) , mapping a tuple onto one of the tuple components
Projection (linear algebra) , idempotent linear mapping
Projection (statistics) , deriving a value from two statistical values
in which geometry is the mapping of three-dimensional objects on a two-dimensional plane, see descriptive geometry
in cartography the representation of the curved surface of the earth in the plane, see map network design
in computer science the selection of attributes from a relation, see Relational Algebra #Projection

Additional:

Projection (optics) , imaging of an object or its image on an image plane through a lens
Projection (psychoanalysis) , unconscious shifting of inner-psychological content onto other people or objects
Projection (nervous system) , relocation of a sensory impression to a specific point in the nervous system
linguistically the passing on of characteristics in a structure, see head (grammar)

See also:

Wiktionary: Projection - explanations of meanings, word origins, synonyms, translations