rea·son (rḗzən)

---

[Middle English, from Old French raison, from Latin ratiō, ratiōn-, from ratus past participle of rērī, to consider, think.]

noun 

1. The basis or motive for an action, decision, or conviction. See Usage Note at: because See Usage Note at: why
2. A declaration made to explain or justify action, decision, or conviction: inquired about her reason for leaving.
3. An underlying fact or cause that provides logical sense for a premise or occurrence: There is reason to believe that the accused did not commit this crime.
4. The capacity for logical, rational, and analytic thought; intelligence.
5. Good judgment; sound sense.
6. A normal mental state; sanity: He has lost his reason.
7. Logic A premise, usually the minor premise, of an argument.

verb: -soned, -son·ing, -sons. 

intransitive verb 

1. To use the faculty of reason; think logically.
2. To talk or argue logically and persuasively.
3. Obsolete To engage in conversation or discussion.

transitive verb 

1. To determine or conclude by logical thinking: reasoned out a solution to the problem.
2. To persuade or dissuade (someone) with reasons.

idioms

by reason of

Because of.

in reason

With good sense or justification; reasonably.

within reason

Within the bounds of good sense or practicality.

with reason

With good cause; justifiably.

derivatives

reáson·er

noun

synonyms:

reason, intuition, understanding, judgment These nouns refer to the intellectual faculty by which humans seek or attain knowledge or truth. Reason is the power to think rationally and logically and to draw inferences: “Mere reason is insufficient to convince us of its veracity” (David Hume) Intuition is perception or comprehension, as of truths or facts, without the use of the rational process: I trust my intuitions when it comes to assessing someone's character. Understanding is the faculty by which one understands, often together with the resulting comprehension: “The greatest dangers to liberty lurk in insidious encroachment by men of zeal, well-meaning but without understanding” (Louis D. Brandeis) Judgment is the ability to assess situations or circumstances and draw sound conclusions: “At twenty years of age, the will reigns; at thirty, the wit; and at forty, the judgment” (Benjamin Franklin)

See also: cause

See also: mind

See also: think