asañña-satta: The 'unconscious beings', are a class of heavenly beings in the fine-material world; s. deva (II). "There are, o monks, heavenly beings known as the unconscious ones. As soon, however, as in those beings consciousness arises, those beings will vanish from that world. Now, o monks, it may happen that one of those beings after vanishing from that world, may reappear in this world...." (D. 24). Further details, s. Kath., Yam. (Guide, pp. 68, 79, 96 ff.).

Buddhist Dictionary, Manual of Buddhist Terms and Doctrines, by NYANATILOKA MAHATHERA