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sine qua non

[sahy-nee kwey non, kwah, sin-ey; Latin si-ne kwah-nohn]
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noun

an indispensable condition, element, or factor; something essential: Her presence was the sine qua non of every social event.

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RELATED WORDS

arrangement, article, catch, codicil, contingency, demand, essential, exception, exemption, kicker, modification, must, necessity, need, postulate, precondition, prerequisite, provision, proviso, qualification

Origin of sine qua non

From the Late Latin word sine quā (causā) nōn without which (thing) not

causa sine qua non

[kou-sah si-ne kwah nohn; English kaw-zuh sahy-nee kwey non, kaw-zuh sin-ey kwah nohn]

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
British Dictionary definitions for sine qua non

sine qua non

noun

an essential condition or requirement

Word Origin for sine qua non

literally: without which not
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for sine qua non

"an indispensable condition," Latin, literally "without which not," from sine "without" (see sans) + qua ablative fem. singular of qui "which" (see who) + non "not" (see non-). Feminine to agree with implied causa. The Latin phrase is common in Scholastic use. Sometimes a masculine form, sine quo non, is used when a person is intended. Proper plural is sine quibus non.

Online Etymology Dictionary, © 2010 Douglas Harper
Culture definitions for sine qua non

sine qua non

[(sin-i kwah non, nohn)]

The essential, crucial, or indispensable ingredient without which something would be impossible: “Her leadership was the sine qua non of the organization's success.” From Latin, meaning “without which nothing.”

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Idioms and Phrases with sine qua non

sine qua non

An essential element or condition, as in A perfect cake is the since qua non of a birthday party. This phrase is Latin for “without which not” and has been used in English since about 1600. It appears more in writing than in speech.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.