a sine qua non

(formal)

something that is necessary, especially if you are going to achieve a particular thing (often + of ) The company sees training as the sine qua non of success.

Common Names:

Name	Pronounced	Usage
Massoud	-	Persian
Drago	-	Croatian, Serbian, Slovene
Gerasimos	-	Greek
Ioana	-	Romanian, Bulgarian
Victorius	-	Late Roman
Merrick	MER-ik	English (Rare)