Noun

• S: (n) reason (reason%1:16:00::), ground (ground%1:16:00::) (a rational motive for a belief or action) "the reason that war was declared"; "the grounds for their declaration"
• S: (n) reason (reason%1:10:01::) (an explanation of the cause of some phenomenon) "the reason a steady state was never reached was that the back pressure built up too slowly"
• S: (n) reason (reason%1:09:00::), understanding (understanding%1:09:00::), intellect (intellect%1:09:01::) (the capacity for rational thought or inference or discrimination) "we are told that man is endowed with reason and capable of distinguishing good from evil"
• S: (n) rationality (rationality%1:26:00::), reason (reason%1:26:00::), reasonableness (reasonableness%1:26:00::) (the state of having good sense and sound judgment) "his rationality may have been impaired"; "he had to rely less on reason than on rousing their emotions"
• S: (n) cause (cause%1:10:00::), reason (reason%1:10:00::), grounds (grounds%1:10:00::) (a justification for something existing or happening) "he had no cause to complain"; "they had good reason to rejoice"
• S: (n) reason (reason%1:09:01::) (a fact that logically justifies some premise or conclusion) "there is reason to believe he is lying"

Verb

• S: (v) reason (reason%2:31:01::), reason out (reason_out%2:31:00::), conclude (conclude%2:31:00::) (decide by reasoning; draw or come to a conclusion) "We reasoned that it was cheaper to rent than to buy a house"
• S: (v) argue (argue%2:32:02::), reason (reason%2:32:00::) (present reasons and arguments)
• S: (v) reason (reason%2:31:00::) (think logically) "The children must learn to reason"