In behavior, normal refers to a lack of significant deviation from the average. The phrase “not normal” is often applied in a negative sense (asserting that someone or some situation is improper, sick, etc.). Abnormality varies greatly in how pleasant or unpleasant this is for other people; somebody may half-jokingly be called “pleasantly disturbed”.

In mathematics, normal can have several meanings:

Surface normal, a line that is perpendicular to a surface.

Normal component, the component of a vector that is perpendicular to a surface.

Normal curvature, of a curve on a surface, the component of curvature that is normal to the surface

Normal distribution, a type of probability distribution in probability theory and statistics.

Normal extension, in abstract algebra, a certain type of algebraic field extensions.

Normal equations, for linear least squares, a model fitting technique using projection matrices.

Normal family, a pre-compact family of holomorphic functions.

Normal function, a continuous strictly increasing function from ordinals to ordinals.

Normal matrix, a matrix which commutes with its conjugate transpose.

Normal mode, a special type of solution in an oscillating system.

Normal morphism, is a morphism that arises as the kernel or cokernel of some other morphisms.

Normal number (computing), a number that is within the normal range of a floating-point format.

Normal number, a number whose digit sequence is random.

Normal operator, a linear operator on a Hilbert space that commutes with its adjoint.

Normal ring, a ring that is its own integral closure in its field of fractions.

Normal space, a topological space in which disjoint closed sets can be separated by disjoint neighborhoods.

Normal subgroup, a subgroup that is invariant under conjugation in abstract algebra.

Normal polytope, a lattice polytope in which dilation of points is given by summing lattice points.

Normal measure, a particular type of measure on a measurable cardinal.

Seriously…the ideal of the ‘norm’ is really a misrepresentation of what society chooses as the most comfortable mode of acceptance. Too bad it often leaves the elderly, young and disabled out of the loop, and loses the wonderful gifts that each of them have to share. HTH

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