maybe worth considering what isn’t a holonomic system:
http://en.wikipedia.org/wiki/Non-holonomic_system
wiki: A nonholonomic system in physics and mathematics is a system whose state depends on the path taken to achieve it. Such a system is described by a set of parameters subject to differential constraints, such that when the system evolves along a path in its parameter space (the parameters varying continuously in values) but finally returns to the original set of values at the start of the path, the system itself may not have returned to its original state.
More precisely, a nonholonomic system, also called an anholonomic system, is one in which there is a continuous closed circuit of the governing parameters, by which the system may be transformed from any given state to any other state
Note the examples given, a simple pedulum versus the Foucault pendulum.
I tend to think of them as static vs. dynamic systems, which isn’t quite correct, but all my brain can cope with. I’m sure I’ve read a more concise explantion somewhere, but my physics textbooks are at home.