sine qua non

American  

[sahy-nee kwey non, kwah, sin-ey, si-ne kwah-nohn] / ˈsaɪ ni kweɪ ˈnɒn, kwɑ, ˈsɪn eɪ, ˈsɪ nɛ kwɑˈnoʊn /

noun

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

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

---

sine qua non British  

/ ˈsaɪnɪ kweɪ ˈnɒn /

noun

1. an essential condition or requirement

---

sine qua non Cultural  

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.”

---

sine qua non Idioms  

1. 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.

---

Etymology

Origin of sine qua non

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

Example Sentences

The image of Toyotas and Datsuns — soon rebranded as Nissans — went from quirky to sine qua non.

From Los Angeles Times

This is the sine qua non of self-defense.

From The Wall Street Journal

In fact, the history of whaling on its own disproves the central point of “The Killing Age,” that guns were a sine qua non for the making of the modern world.

From The Wall Street Journal

“But now speed and maneuverability are the sine qua non.”

From The Wall Street Journal

What I did in the meantime — because I knew that I had to be there and eat the food, and know the people, and that was sine qua non.

From Los Angeles Times