1. (

• reason ,
• ground

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

2. (

• 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. (

• 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. (

• 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. (

• 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" ;

1. (

• 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. (

• argue ,
• reason

) present reasons and arguments ;

3. (

• reason

) think logically; "The children must learn to reason" ;