I'm a structure, you're a structure we're all structures. Kinematic structures actually. People, robots, animals and moving beings of all sorts can be described using kinematic models.
According to the standard a kinematic structure (section 5.4.8): "A kinematic_structure specifies the topological aspects of a kinematic representation. The topology of the kinematic_structure is represented by means of kinematic_joints which, in turn, establish a relationship between pairs of kinematic_links."