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raison d'etre

[rey-zohn de-truh, re-zawn de-truh] / ˈreɪ zoʊn ˈdɛ trə, rɛ zɔ̃ ˈdɛ trə /
NOUN
reason for being
Synonyms
WEAK
basis justification for existing rationale reason for existing reason why
raison d'être
NOUN
reason for being
Synonyms
WEAK
basis justification for existing rationale reason for existing reason why

From Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.