2. Realm of Form (Sanskrit word is Rupaadhatu) of matter which is substantial and resistant. It is a semi material conception. It is above the lust world and contains bodies, places and things, all mystic and wonderful. It consists of 18 heavens, including the Heavens of Four Zen (Sanskrit word is Brahmalokas).
3. Realm of Formlessness (Sanskrit word is Arupadhatu) of pure spirit, where there are no bodies and matters to which human terms would apply, but where the mind dwells in mystic contemplation; its extent is indefinable, but it is conceived of in Four Stages/Places of Emptiness in the immaterial world.
The three levels within samsara: the desire realm, the form realm, and the formless realm. The desire realm is the environment of hell beings, hungry spirits, animals, human beings, demi gods, and the gods who enjoy the five objects of desire. The form realm is the environment of the gods who possess form. The formless realm is the environment of the gods who do not possess form. Beings of the desire realm have powerful delusions, beings of the form realm have more subtle delusions, and beings of the formless realm have very subtle delusions.