# Normal

Normal may refer to:

## Mathematics

There are many unrelated notions of "normality" in mathematics.

### Analysis

• Normal family, a pre-compact family of continuous functions
• 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

### Geometry

• Normal (geometry), a vector perpendicular to a surface (normal vector)
• Normal bundle, a term related to the preceding concept
• Normal cone, of a subscheme in algebraic geometry
• 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
• Normal space (or ${\displaystyle T_{4}}$) spaces, topological spaces characterized by separation of closed sets

### Probability and statistics

• Normal, the middle 95% of a bell curve (see 1.96)
• Normal distribution, the Gaussian continuous probability distribution

## Transport

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