I. ˈnȯr-məl adjective
Etymology: Latin normalis, from norma
Date: circa 1696
1. : perpendicular ; especially : perpendicular to a tangent at a point of tangency
2.
a. : according with, constituting, or not deviating from a norm, rule, or principle
b. : conforming to a type, standard, or regular pattern
3. : occurring naturally
normal immunity
4.
a. : of, relating to, or characterized by average intelligence or development
b. : free from mental disorder : sane
5.
a. of a solution : having a concentration of one gram equivalent of solute per liter
b. : containing neither basic hydroxyl nor acid hydrogen
normal silver phosphate
c. : not associated
normal molecules
d. : having a straight-chain structure
normal pentane
normal butyl alcohol
6. of a subgroup : having the property that every coset produced by operating on the left by a given element is equal to the coset produced by operating on the right by the same element
7. : relating to, involving, or being a normal curve or normal distribution
normal approximation to the binomial distribution
8. of a matrix : having the property of commutativity under multiplication by the transpose of the matrix each of whose elements is a conjugate complex number with respect to the corresponding element of the given matrix
Synonyms: see regular
• nor·mal·i·ty nȯr-ˈma-lə-tē noun
• nor·mal·ly ˈnȯr-mə-lē adverb
II. noun
Date: circa 1738
1.
a. : a normal line
b. : the portion of a normal line to a plane curve between the curve and the x-axis
2. : one that is normal
3. : a form or state regarded as the norm : standard