Incidentally if you look at the word origin of Holarchy (also known as Holoarchy) Hol-archy then you will realise that it has the same root 'Hol-' from Holon meaning an Autonomous self reliant unit, which in turn is derived from (gk) Holo- meaning whole (This is the concept on which the governance model is built and the anchor point of Self-Management); 'archy' from Greek -arkhia "rule," from arkhos "leader, chief, ruler," from arkhe "beginning,origin, first place".
What is the difference then between Holacracy and Holarchy? Well, Holacracy denotes the METHOD/system/process of the power distribution (governance), where as Holarchy denotes the ORIGIN of that power (seat). So you could say that a Holacracy is enabled through the existence of a Holarchy. Hope this makes sense.