Normal

Normal may refer to:

People

• Henry Normal an English comedian

Psychology and social sciences

• Normality (behavior), conformance to an average
• Norm (social), expected patterns of behavior studied within the context of sociology
• Normal goods, a concept used in economics
• Normal backwardation, a stock market term
• Norm, a statistical concept in psychometrics

Chemistry

• Normal concentration, a measure of concentration for a chemical in a solution

Education and teaching

• Normal school, a school created to train high school graduates to be teachers

Technology

• Normal lens (photography), a lens of moderate focal length

Arts and entertainment

• Normal (2003 film), starring Jessica Lange and Tom Wilkinson
• Normal (2007 film), starring Carrie-Anne Moss, Kevin Zegers, Callum Keith Rennie and Andrew Airlie
• Normal (2009 film), an adaptation of Anthony Neilson's 1991 play Normal: The Düsseldorf Ripper
• Normal (album), a 2005 album by Ron "Bumblefoot" Thal
• The Normals, a Christian alternative rock band formed in 1998
• Normal!, a 2011 Algerian film

Mathematics

There is an extremely large number of unrelated notions of "normality" in mathematics. The following list is no doubt incomplete. See also the disambiguation pages for Normal form and Normalization.

Algebra and Number Theory

• Normal subgroup, a subgroup invariant under conjugation
• Normal extensions (or quasi-Galois) field extensions, splitting fields for a set of polynomials over the base field
• Normal domain (integrally closed domain), a ring integrally closed in its fraction field
  • Normal ring, a reduced ring whose localizations at prime ideals are integrally closed domains
  • Normal scheme, an algebraic variety or scheme that meets certain conditions
• Normal variety, a projective variety embedded by a complete linear system, as in a rational normal scroll (unrelated to the concept of normal scheme above)
• Normal basis (of a Galois extension), used heavily in cryptography
• Normal order of an arithmetic function, a type of asymptotic behavior useful in number theory
• Normal degree, a rational curve on a surface that meets certain conditions

Analysis

• Normal number, a real number with a "uniform" distribution of digits
• Normal number (computing), a floating-point number within the balanced range supported by a given format (unrelated to the previous notion)
• Normal operator, an operator that commutes with its Hermitian adjoint
  • Normal matrix, a complex square matrix that meets certain conditions
• Normal modes of vibration in an oscillating system
• Normal family, a pre-compact family of continuous functions

Geometry

• Normal (geometry), a vector perpendicular to a surface (normal vector)
• Normal bundle, a term related to the preceding concept
• Normal coordinates in differential geometry, local coordinates obtained from the exponential map (Riemannian geometry)
• Normal invariants in geometric topology
• Normal polytopes in polyhedral geometry and computational commutative algebra

Logic and Foundations

• Normal functions in set theory
• Normal measures in set theory

Mathematical Physics

• Normal order or Wick order in Quantum Field Theory

Probability and Statistics

• Normal distribution, the Gaussian continuous probability distribution

Topology

• Normal space (or $T_4$) spaces, topological spaces characterized by separation of closed sets

Geography

• Normal, Alabama
• Normal, Illinois
• Normal, Indiana
• Normal Station, Memphis

Transport

• Metro Normal, a rapid transit railway station in the Mexico City Metro system