(1) In the Gelug non-Kalachakra system, the voidness of a Buddha's omniscient mind and its state of being parted from the two sets of obscurations. (2) In the Gelug Kalachakra system, the blissful awareness aspect of a Buddha's omniscient mind. (3) In the Non-Gelug systems, the inseparability of all the Corpuses of a Buddha - equivalent to the inseparability of the two truths.
Tibetan: ངོ་བོ་ཉིད་སྐུ། ngo-bo-nyid sku
Synonyms: Body of Essential Nature; Corpus of Essential Nature; Nature Body; Svabhavikakaya