1. ajñāna or avidyā
Brahman as controlling mayā is Iśvara. Brahman as controlled by mayā is jīva. From the position of the jīva, this mysterious principle, māyā, is designated as ajñāna or avidyā, which is usually translated as ignorance or nescience. But ajñāna or avidyā does not mean the absence or the negation, but the reverse, of knowledge. It is antiknowledge, which terminates with the knowledge of Reality.
2. mithyā
Since the world of becoming is indescribable (anirvacanīya) either as real (sat) or as unreal (asat), it is characterized in Vedantic terminology as mithyā, which does not mean, as is often misconceived, "unreal" but "other than real and unreal" (sadasad-vilaksņa). The manifold has an apparent existence grounded on the Supreme Being like the illusory appearance of a serpent on a rope.
3. Māyā
That which is real in Māyā is the Reality in and through Māyā. Yet the Reality is not seen, and hence that which is seen is unreal and it has no real independent existence of itself, but is dependent upon the Real for its existence. Māyā then is a paradox - real, yet not real; an illusion, yet not an illusion. He who knows the Real sees in Māyā not illusion but Reality. He who knows not the Real sees in Māyā illusion and thinks it real. ~Vivekananda (as quoted by S)



