Tathagatagarbha or Buddha-Nature (Skt.  buddhadhātu )  is a Mahayana term, which tries to describe the true nature of Nirvana. Buddha-Nature stands from the Mahayana sight  for the existence of an eternal and imperishable self. But Tathāgatagarbha has a wide range of (often conflicting) meanings in Indian and later East Asian and Tibetan Buddhist literature, as an emptiness that is a nonimplicative negation, the luminous nature of the mind or alaya-vijñana (store-consciousness) , conflicting with the anatta - teachings.

The Tathāgatagarbha Sūtra (or Nirvana Sutra)  is an influential and doctrinally striking Mahāyāna Buddhist scripture which treats of the existence of the "Tathāgatagarbha" (Buddha-Matrix, Buddha-Embryo, Buddha-Essence, lit. "the womb of the thus-come-one") within all sentient creatures. The Buddha reveals how inside each person's being there exists a great Buddhic "treasure that is eternal and unchanging". This is no less than the indwelling Buddha himself.