I think the way I remember hearing Geoff put it was something like this:
Permaculture is like a clothing rack. Things like agroforestry,
aquaculture, integrated orchards and paddock shift grazing are all hangers on the rack. In other words, all the other minor methods, techniques and practices fall under the realm of permaculture when practiced wisely. Permaculture includes all that meet the standards of the three ethics. At least that was my take on it.