Large-Scale Scrum (LeSS) is a framework for scaled agile and scaling Scrum. LeSS decreases organizational complexity. It's a product development framework that extends Scrum with scaling rules and guidelines without losing the original purposes of Scrum.
LeSS stands for the general techniques for scaling Scrum and Agile Development to more than one team and it is the name for the basic LeSS Framework which works up-to around 8 teams.