Etymology: Latin normalis, from norma
Date: circa 1696
1. perpendicular; especially perpendicular to a tangent at a point of tangency
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 • normality noun • normally 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
New Collegiate Dictionary. 2001.