Kinematics: Some Definitions

Kinematics:

concerns itself with all the geometrical and time-related properties of  motion,
such as position, velocity, acceleration of rigid bodies,
independent of the underlying forces that produce the motion.

Articulated Skeleton:

is a structure consisting of a series of rigid links connected via joints.

End Effector:

Most industrial manipulators are open-ended chains of links,
and the free end of such a chain is called the end effector (Example: the hand on an arm).

Degrees of Freedom (DoF):

the number of independent position variables necessary to specify the state of an articulated structure.

State Vector:

is the vector of all the parameter values for all the joints that completely characterizes the geometry of the articulated figure.