Reason

Part of speech: noun, verb

Pronunciation: /ˈɹiːzn̩/

Definitions

1. The ability to think logically and draw conclusions, or a cause or justification for an action or belief
2. The cognitive process of evaluating situations to form judgments or conclusions, and the underlying justification or rationale for an action or belief
3. A mental faculty that allows people to analyze information, make inferences, and decide what is true or appropriate ; a ground or motive that explains why something happens or why someone acts in a certain way ; a principle or argument used to persuade or justify a decision

Etymology: Reason has two unrelated ancestors that happen to share a spelling. The sense "cause or logical thinking" comes from Latin "ratio," meaning "calculation" or "reckoning," from "ratus," the past participle of "reor" ("reckon"). It reached English through Anglo-Norman "raisun" and Old French "raison," and Middle English "resoun" was already in use by then. Its close relatives are "ration" and "ratio," which entered English from the same Latin word by a different route. Old English had its own word for logic, "racu," but it was displaced by the Latin-derived form. A native Middle English word "reden," from Old English "rǣden" meaning "condition" or "direction," survives only in compounds, and it is cognate with Dutch "reden," which still means "reason." The other "reason" is a separate word. It comes from Old English "ræsn," meaning "beam" or "rafter," a timber in a roof or ceiling. Its ancestor was a word for "house."

Synonyms: cause, motive, justification, explanation, basis

Antonyms: irrationality, absurdity, nonsense, foolishness, unreason