reason

/ˈrē-zᵊn/

Middle English resoun, from Anglo-French raisun, from Latin ration-, ratio "reckoning, calculation, explanation," from reri "to calculate, think;" probably akin to Goth rathjo "account, explanation"

noun

  1. a statement offered in explanation or justification

  2. a rational ground or motive

  3. the thing that makes some fact intelligible : cause

gave reasons that were quite satisfactory

a good reason to act soon

verb

  1. to use the faculty of reason so as to arrive at conclusions

  2. to talk with another so as to influence actions or opinions

  3. to take part in conversation, discussion, or argument

think cogitate reflect reason speculate deliberate mean to use one's powers of conception, judgment, or inference. think is general and may apply to any mental activity, but used alone often suggests attainment of clear ideas or conclusions. cogitate implies deep or intent thinking.

phrasal verb

  1. to find an explanation or solution to (something, such as a problem, question, mystery, etc.) by thinking about the possibilities

He reasoned out the problem by himself.