The term first appears in the Mahāyāna recension of the ''Mahāparinirvāṇasūtra'', now available only in Chinese translation, which states that all sentient beings have the “buddha-element” (''foxing''). (The Chinese translation ''foxing'' literally means “buddha-nature” and the Chinese has often been mistakenly back-translated as the Sanskrit buddhatā; buddhadhātu is the accepted Sanskrit form.) The origin of the term may, however, be traced back as far as the ''Aṣṭasāhasrikāprajñāpāramitā'', one of the earliest Mahāyāna Sūtras, where the fundamental substance of the mind is said to be luminous (''prakṛtiś cittasya prabhāsvarā''), drawing on a strand of Buddhism that has its antecedents in such statements as the Pāli ''Aṅguttaranikāya'': “The mind, O monks, is luminous but defiled by adventitious defilements” (''pabhassaraṃ idaṃ bhikkhave cittaṃ, tañ ca kho āgantukehi upakkilesehi upakkiliṭṭhaṃ''). Because the bodhisattva realizes that the buddha-element is inherent in him at the moment that he arouses the aspiration for enlightenment (''bodhicittotpāda'') and enters the bodhisattvayāna, he achieves the profound endurance (''kṣānti'') that enables him to undertake the arduous training, over not one, but three, incalculable eons of time (''asaṃkhyeyakalpa''), that will lead to buddhahood. The buddhadhātu is a seminal concept of the Mahāyāna and leads to the development of such related doctrines as the “matrix of the tathāgatas” (''tathāgatagarbha'') and the “immaculate consciousness” (''amalavijñāna''). - ''Princeton Dictionary of Buddhism'' (2014), pages 151-152. +