Basic Meaning
A synonym for tathāgatagarbha widely used throughout the East Asian Buddhist traditions, as found in its translations as the Chinese term fó xìng and Japanese term busshō.
Has the sense of
This is most likely the direct source of the English term buddha-nature via its translation into Chinese and Japanese. These traditions tended to treat the Sanskrit terms dhātu, gotra, and garbha as synonyms when compounded with the term buddha, though the translation of buddhadhātu seems to have been adopted as the standard technical term to reference the buddha-nature doctrine, as it could cover a wider range of possible meanings. In other words, the term dhātu could more easily reference both the causal aspect of this nature, commonly associated with the term gotra, and the fruition aspect of this nature, commonly associated with the term garbha.
In Sanskrit, “buddha-element,” or “buddha-nature”; the inherent potential of all sentient beings to achieve buddhahood. See page 151.
Literally, "buddha-element," a synonym for what Rongtön calls natural buddha-nature or undefiled suchness. It is the empty nature of the mind, identical in both sentient beings and buddhas. - Bernert, Christian, Perfect or Perfected? Rongtön on Buddha-Nature (2018), page 114.
On this topic