Definition of: rational

(rash′ən·əl) adjective
1. Possessing the faculty of reasoning.
2. Conformable to reason; judicious; sensible.
3. Pertaining to reason; attained by reasoning.
4. Pertaining to rationalism.
5. Math. a Pertaining to a rational number. b Denoting an algebraic expression containing variables within radicals, as . Compare IRRATIONAL.
6. In Greek and Latin prosody, denoting the measurement of metrical units; capable of being measured in metrical units.
—noun That which is rational. [<L rationalis <ratio, -onis]
—ra′tion·al·ly adverb
—ra′tion·al·ness noun Synonym (adj.): reasonable. A rational mind is one that is capable of the ordinary and normal processes of thought; a reasonable mood is one at the time susceptible to the influence of reasons. A rational man is capable of using his reasoning powers; a reasonable man has them habitually in exercise. Rational is opposed to insane, reasonable to fanatical, misguided, obstinate, unreasonable, visionary. See SAGACIOUS, SANE¹, WISE¹.