causa sine qua non

[ kou-sah si-ne kwah nohn; English kaw-zuh sahy-nee kwey non, kaw-zuh sin-ey kwah nohn ]
/ ˈkaʊ sɑ ˈsɪ nɛ kwɑ ˈnoʊn; English ˈkɔ zə ˈsaɪ ni kweɪ ˈnɒn, ˈkɔ zə ˈsɪn eɪ kwɑ ˈnoʊn /

noun Latin.

an indispensable condition; requisite.

Origin of causa sine qua non

literally, a cause without which not
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019