Unity is the most widely reported feature of mystical experience and a central idea of the contemplative philosophies: the One of Plotinus, the tawḥīd of Islam, the ekam of the Upaniṣads, the Dao that gives birth to the one. Traditions differ on whether unity erases distinction or holds it, as when the drop merges with the ocean or the iron glows in the fire.
Unity
Oneness: the experience or doctrine that all things are one, or one with their source.
Also: oneness