define conditio sine qua non
Sine qua non. For other uses, see Sine qua non (disambiguation). Sine qua non (/ËsaÉªni kweÉª ËnÉn/; Latin: [Ësine kwaË ËnoËn]) or conditio sine qua non (plural: conditiones sine quibus non) is an indispensable and essential action, condition, or ingredient. It was originally a Latin legal term for [a condition] without which it could not be, or but for... or without which [there is] nothing.