真如

Bhūta-tathatā in Sanskrit word. Bhūta means substance that exists; tathatā means suchness, i.e. such is its nature. It is regarded as the absolute, ultimate source and character of all phenomena. It is the eternal, imperson, unchangeable reality behind all phenomena. Simply speaking, it is ALL.

There are many other terms to describe it, e.g. Buddha-nature, Self-nature Pure Mind, Dharmakāya (Dharma Body), Tathāgata-garbha (Buddha-treasury), Reality (real mark), Dharma Realm, Dharma Nature, the Complete and Perfect real nature, etc.