- n. m.1. Prouver par a+b: To prove by logical reasoning, with mathematical precision.2. C'est l'abc du métier: It's one of the first things you learn.3. De A jusqu'à Z: Through and through, thoroughly. (This expression is sometimes used in a jocular and ironic way describing a lax approach to a demanding task; it is worth noting that on a French typewriter A and Z are adjacent on the keyboard.)
Dictionary of Modern Colloquial French. 2013.