The noun reason has 6 senses (first 5 from tagged texts)
1. (78) reason, ground -- (a rational motive for a belief or action; "the reason that war was declared"; "the grounds for their declaration")
2. (32) reason -- (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")
3. (3) reason, understanding, intellect -- (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")
4. (1) rationality, reason, reasonableness -- (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")
5. (1) cause, reason, grounds -- (a justification for something existing or happening; "he had no cause to complain"; "they had good reason to rejoice")
6. reason -- (a fact that logically justifies some premise or conclusion; "there is reason to believe he is lying")
Overview of verb reason
The verb reason has 3 senses (first 3 from tagged texts)
1. (3) reason, reason out, conclude -- (decide by reasoning; draw or come to a conclusion; "We reasoned that it was cheaper to rent than to buy a house")
2. (2) argue, reason -- (present reasons and arguments)
3. (1) reason -- (think logically; "The children must learn to reason")