Etymology: Middle English resoun, from Anglo-French raisun, from Latin ration-, ratio reason, computation, from reri to calculate, think; probably akin to Gothic rathjo account, explanation
Date: 13th century
a. a statement offered in explanation or justification <gave reasons that were quite satisfactory> b. a rational ground or motive <a good reason to act soon> c. a sufficient ground of explanation or of logical defense; especially something (as a principle or law) that supports a conclusion or explains a fact <the reasons behind her client's action> d. the thing that makes some fact intelligible ; cause <the reason for earthquakes> <the real reason why he wanted me to stay — Graham Greene> 2. a. (1) the power of comprehending, inferring, or thinking especially in orderly rational ways ; intelligence (2) proper exercise of the mind (3) sanity b. the sum of the intellectual powers 3. archaic treatment that affords satisfaction II. verb (reasoned; reasoning) Date: 15th century intransitive verb 1. a. obsolete to take part in conversation, discussion, or argument b. to talk with another so as to influence actions or opinions <can't reason with them> 2. to use the faculty of reason so as to arrive at conclusions transitive verb 1. archaic to justify or support with reasons 2. to persuade or influence by the use of reason 3. to discover, formulate, or conclude by the use of reason <a carefully reasoned analysis> Synonyms: see think • reasoner noun
New Collegiate Dictionary. 2001.