Basic Meaning
Literally, the "essence" or "heart of the Bliss Gone One(s)," a synonym for tathāgatagarbha that is likewise often rendered into English by the term buddha-nature. Though it is often back translated into Sanskrit as sugatagarbha, this term is not found in Sanskrit sources.
Has the sense of
The essence of enlightenment present in all sentient beings.
This term is used differently depending on the context: in a sūtric context, the term is equivalent to tathāgatagarbha and is translated into English as "buddha-nature". In a tantric context, depending upon the tradition, sugatagarbha is a synonym for pristine awareness and emptiness.
See page 865: in Sanskrit, “essence of the sugata,” a synonym for tathāgatagarbha.
sugata-essence, enlightened essence, essence for attaining experience of bliss. Sugatagarbha. 'Sugata essence.' The most common Sanskrit term for what in the West is known as 'buddha-nature.'
sems can thams cad kyi rgyud la ye nas gnas pa'i gzhi rgyud bde bar gshegs pa'i snying po ngo bo stong pa rang bzhin gsal ba thugs rje kun khyab kyi bdag nyid can
On this topic