Dharmadhātu is the sphere or ground of all dharmas, the whole of reality as it truly is. In Huayan it is the cosmos of interpenetrating phenomena; in the Yogācāra and tathāgatagarbha traditions it is suchness, the purity underlying all things. The word also names the space of awakening in Tibetan thought.
Dharmadhātu
The realm of reality: the totality of all phenomena in their true nature.
Also: Dharmadhatu