In defining the scope of our subject, we have to establish the genealogy of robotic mechanical systems. These are, obviously, a subclass of the much broader class of mechanical systems. Mechanical systems, in turn, constitute a subset of the more general concept of dynamic systems. In the end, we must have an idea of what, in general, a system is.
The Concise Oxford Dictionary defines system as a "complex whole, set of connected things or parts, organized body of material or immaterial things," whereas the Random House College Dictionary defines the same as "an assemblage or combination of things or parts forming a complex or unitary whole." Le Petit Robert, in turn, defines system as "Ensemble possedant une structure, constituant un tout organique," which can be loosely translated as "A structured assemblage constituting an organic whole." In the foregoing definitions, we note that the underlying idea is that of a set of elements interacting as a whole.