Available Definitions:
1) a. - Relating to the reason; not physical; mental.
2) a. - Having reason, or the faculty of reasoning; endowed with reason or understanding; reasoning.
3) a. - Agreeable to reason; not absurd, preposterous, extravagant, foolish, fanciful, or the like; wise; judicious; as, rational conduct; a rational man.
4) a. - Expressing the type, structure, relations, and reactions of a compound; graphic; -- said of formulae. See under Formula.
5) n. - A rational being.