sine qua non

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

noun

1. an indispensable condition, element, or factor; something essential:

   Her presence was the sine qua non of every social event.

sine qua non

/ ˈsaɪnɪ kweɪ ˈnɒn /

noun

1. an essential condition or requirement

sine qua non

1. 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.”

Word History and Origins

Origin of sine qua non¹

From Late Latin sine quā (causā) nōn “without which (thing) not”

Word History and Origins

Origin of sine qua non¹

literally: without which not

Idioms and Phrases

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.