Definition of: normal

(nôr′məl) adjective
1. In accordance with an established law or principle; conforming to a type or standard; regular; natural.
2. Constituting a standard; model.
3. Math. Of, pertaining to, or constituting a normal; perpendicular.
4. Average; mean.
5. Chem. a Denoting a molecular structure based on an unbranched chain of carbon atoms. b Denoting a salt containing no replaceable hydrogen or hydroxide radical. c Denoting an aqueous solution containing one gram equivalent of the active solute in one liter of solution.
6. Biol. Designating a condition not exposed to or modified by special experimental treatment.
7. Psychol. Well adjusted to the outside world; without undue mental tensions.
—noun
1. Math. a A perpendicular; specifically, a perpendicular to a curve or curved surface; a straight line perpendicular to a tangent line or plane at the point of tangency. b The intercept, on the normal line, between the curve and either the X-axis or the center of curvature.
2. A common or natural condition.
3. A usual or accepted rule or process.
4. The average or mean value of observed quantities.
5. An abbreviated expression for normal temperature, volume, etc. [<L normalis <norma rule]
—nor·mal·i·ty (nôr·mal′ə·tē) noun
—nor′mal·ly adverb
—nor′mal·ness noun Synonyms (adj.): common, natural, ordinary, regular, typical, usual. That which is natural is according to nature; that which is normal is according to the standard or rule which is observed or claimed to prevail in nature; a deformity may be natural, symmetry is normal; the normal color of the crow is black, while the normal color of the sparrow is gray, but one is as natural as the other. Typical refers to such an assemblage of qualities as makes the specimen, genus, etc., a type of some more comprehensive group, while normal is more commonly applied to the parts, qualities, etc, of a single object; the specimen was typical; color, size, and other characteristics normal. The regular is that which is steady and constant, as opposed to that which is fitful and changeable; the normal action of the heart is regular. That which is common or usual is shared by a great number of persons or things. See COMMON, GENERAL, NATURAL, USUAL. Antonyms: abnormal, exceptional, irregular, monstrous, rare, uncommon, unprecedented, unusual.