Maya - the veil of illusion that conceals the full experience of Brahman from the Jiva, or individual soul.
Maya is Brahman's power, a result of Brahman - like the heat from fire. Maya causes us to see manifold reality, instead of the one Reality.
In Advaita Vedanta philosophy, Maya is the limited, purely physical and mental reality in which our everyday consciousness has become entangled. Maya is held to be an illusion, a veiling of the true, unitary Self — the Cosmic Spirit also known as Brahman. The concept of Maya was expounded in the Hindu scriptures known as the Upanishads. Many philosophies or religions seek to "pierce the veil" of Maya in order to glimpse the transcendent truth, from which the illusion of a physical reality springs, drawing from the idea that first came to life in the Hindu stream of Vedanta. Maya is neither true nor untrue. Since Brahman is the only truth, Maya cannot be true. Since Maya causes the material world to be seen, it cannot be untrue. Hence, Maya is described as indescribable. She has two principle functions — one is to veil Brahman and obscure and conceal it from our consciousness. The other is to present and promulgate the material world and the veil of duality instead of Brahman. The veil of Maya is piercable and with dilligence and grace, may be permanently rent. Consider an illusion of a rope being confused as a snake in the darkness. Just as this illusion gets destroyed when true knowledge of the rope is perceived, similarly, Maya gets destroyed for a person when they perceive Brahman with transendental knowledge. A metaphor is also given — when the reflection of Brahman falls on Maya, Brahman appears as God (the Supreme Lord). Pragmatically, where the duality of the world is regarded as true, Maya becomes the divine magical power of the Supreme Lord. Maya is the veritable fabric of duality and she performs this role at the behest of the Supreme Lord. God is not bound by Maya, just as a magician is not illusioned and deluded by their own magic.