In this second chapter the authors examines some basic notions and terms relating to directionality. They believe that an examination of this kind is essential, firstly to clarify and define the concepts which appear throughout the remainder of this volume, and secondly, to make clear the premises on which their reflections are based. Their intention is mainly to draw attention to certain terms which traditional Translation Studies literature uses as absolutes and which are believed to merit questioning, rejecting, finetuning or nuancing. In some cases, for this reason, the authors offer alternative proposals, the most significant of these being the case of the term for TNMT itself.