Rational /(răsh"ŭn*al)/

Ra·tion·al

Rational

Relating to the reason; not physical; mental.
Moral philosophy was his chiefest end; for the rational, the natural, and mathematics . . . were but simple pastimes in comparison of the other.
— Sir T. North.
Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning.
It is our glory and happiness to have a rational nature.
— Law.
Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man.
Expressing the type, structure, relations, and reactions of a compound; graphic; -- said of formulae. See under Formula. (Chem.)
What higher in her society thou find'st Attractive, human, rational, love still.
— Milton.

A law may be reasonable in itself, although a man does not allow it, or does not know the reason of the lawgivers.
— Swift.

Rational horizon: See Horizon, 2 (b).
Rational quantity: one that can be expressed without the use of a radical sign, or in exact parts of unity; -- opposed to irrational or radical quantity.
Rational symptom: one elicited by the statements of the patient himself and not as the result of a physical examination.