- Def: Reason 1. a basis or cause, as for some belief, action, fact, event, etc; 2. a statement presented in justification or explanation of a belief or action; 3. the mental powers concerned with forming conclusions, judgments, or inferences; 4. sound judgment; good sense; 5. normal or sound powers of mind; sanity; 6. Logic. a premise of an argument; 7. Philosophy. the faculty or power of acquiring intellectual knowledge, either by direct understanding of first principles or by argument;
- Origin: c.1225, "statement in an argument," also "intellectual faculty that adopts actions to ends," from Anglo-Fr. resoun, O.Fr. raison, from L. rationem (nom. ratio) "reckoning, understanding, motive, cause," from ratus, pp. of reri "to reckon, think," from PIE base *rei- "to reason, count" (cf. O.E. rÊdan "to advise; see read). Meaning "sanity" is recorded from, c.1380. The verb (c.1300) is from O.Fr. raisoner, from L.L. rationare "to discourse." Originally "to question (someone)," sense of "employ reasoning (with someone)" is from 1847, and that of "to think in a logical manner" is from 1593. Phrase it stands to reason is from 1632. Age of Reason "the Enlightenment" is first recorded 1794, as the title of Tom Paine's book;
- Synonyms: acumen, apprehension, argumentation, bounds, brains, comprehension, deduction, dialectics, discernment, generalization, induction, inference, intellect, intellection, judgment, limits, logic, lucidity, marbles, mentality, mind, moderation, propriety, ratiocination, rationalism, rationality, rationalization, reasonableness, reasoning, saneness, sanity, sense, sensibleness, sound mind, soundness, speculation, understanding, wisdom, wit.