Main Entry: si·ne qua non

Pronunciation: \ˌsi-ni-ˌkwä-ˈnän, -ˈnōn also ˌsē-; also ˌsī-ni-ˌkwā-ˈnän\

Function: noun

Inflected Form(s): plural sine qua nons also sine qui·bus non \-ˌkwi-(ˌ)bu̇s- also -ˌkwī-\

Etymology: Late Latin, without which not

Date: 1602

: something absolutely indispensable or essential <reliability is a sine qua non for success>