reason
US /ˈriː.zən/
UK /ˈriː.zən/

1.
raison, motif
a cause, explanation, or justification for an action or event
:
•
The reason for his absence was illness.
La raison de son absence était la maladie.
•
What's your reason for doing that?
Quelle est ta raison de faire ça ?
1.
raisonner, réfléchir
think, understand, and form judgments logically
:
•
He tried to reason with her, but she wouldn't listen.
Il a essayé de la raisonner, mais elle n’a pas voulu écouter.
•
We need to reason through this problem carefully.
Nous devons raisonner ce problème attentivement.