OCCULT MAGICK is a type of magick that could be defined (I'm giving it a stab at least!) as the sorts of magick that arose from and were developed and explored by secret societies. The word "Occult" means "hidden," and the reason for the secrecy was (and sometimes and some places most certainly still is!) that the Practitioners were practicing their art in the context of cultures that considered all magick to be, by definition, Evil. The occult magickians of the Masons, Rosicrucians, Knights Templar, and their spiritual progeny, the Golden Dawn, and modern day O.T.O. at times despise these unfair prejudices, and at times enjoy their notoriety immensely!
Occult magick is firmly rooted in the Western Tradition (arguably it is the foundation of it) and it also accepts tributaries of Egyptian and Kabbalistic magickal traditions. As a member of the Western Tradition, it shares with Natural Magick the employment of the Elemental and Planetary tiers of correspondence. Aside from "natural magick," occult magick will include more magick of entirely human construct or seemingly so, or "revealed" systems like Enochian magick, and the systems of angels and demons such as in the Lesser Key of Solomon.