I humorously call Backbone a MVCn, which is shorthand for Model-View-Collection. There is no traditional controller as other robust JS MVCs state they have. The Collection being, a collection of Backbone Models (super relational-pimped objects, naturally)
It is difficult to grasp the convention to begin with, but once you get your mind around it, it is relatively simple.
My intention is not to explain every ounce of Backbones universal definition and spirituality, many other good people have done that