raison d'être

(redirected from raisons d'être)
Also found in: Dictionary, Thesaurus.
Related to raisons d'être: Raison d etre

somebody's/something's raison d'être

  (formal)
the most important reason why something exists, or the most important thing in someone's life She's never going to retire - work is her raison d'être. Serious, experimental drama was once the raison d'être of the festival but it has now been replaced by comedy and cabaret shows.