raison d'être /ˌreɪˌzoʊnˈdɛtrə/ noun plural raisons d'être /ˌreɪˌzoʊnzˈdɛtrə/ plural raisons d'être /ˌreɪˌzoʊnzˈdɛtrə/ Learner's definition of RAISON D'ÊTRE
[count] formal
: the thing that is most important to someone or something : the reason for which a person or organization exists最重要的事物;存在的理由