Толковый словарь английского языка Oxford English Reference - rational

adj. 1 of or based on reasoning or reason. 2 sensible, sane, moderate; not foolish or absurd or extreme. 3 endowed with reason, reasoning. 4 rejecting what is unreasonable or cannot be tested by reason in religion or custom. 5 Math. (of a quantity or ratio) expressible as a ratio of whole numbers. Phrases and idioms rational dress hist. a style of dress adopted by some women in the late nineteenth century, including bloomers or knickerbockers. rational horizon see HORIZON 1c. Derivatives rationality n. rationally adv. Etymology: ME f. L rationalis (as RATION)