"Whatever appears to be of any value, if it is without relation to Me, has no reality. Know it as My illusory energy, that reflection which appears to be in darkness." (From the Srimad Bhagavatam)

Misconceiving one thing for another thing is called illusion. For example, accepting a rope as a snake is illusion, but the rope is not false. The rope, as it exists in the front of the illusioned person, is not at all false, but the acceptance is illusory. Therefore the wrong conception of accepting this material manifestation as being divorced from the energy of the Lord is illusion, but it is not false. And this illusory conception is called the reflection of the reality in the darkness of ignorance. Anything that appears as apparently not being "produced out of My energy" is called maya. The conception that the living entity is formless or that the Supreme Lord is formless is also illusion.