What is the definition of raison?
Raison, a French word used in the English language has several possible definitions; reason (cause), reason (mental faculties), a common difference of an arithmetic series or common ratio of a geometric series, and the claimed "reason for being" of something or someone.
A person's raison d'etre is their purpose or reason for living. It's why they do things. In French, raison d'etre literally means "reason for being," and in English it means about the same. ... Raison d'etre is a strong term for something that gives a person's life meaning.