reason

a rational motive for a belief or action; "the reason that war was declared"; "the grounds for their declaration"

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"

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"

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"

a justification for something existing or happening; "he had no cause to complain"; "they had good reason to rejoice"

a fact that logically justifies some premise or conclusion; "there is reason to believe he is lying"

decide by reasoning; draw or come to a conclusion; "We reasoned that it was cheaper to rent than to buy a house"

present reasons and arguments

think logically; "The children must learn to reason"