The Mahāvākyas (sing.: mahāvākyam, महावाक्यम्; plural: mahāvākyāni, महावाक्यानि) are "The Great Sayings" of the Upanishads, as characterized by the Advaita school of Vedanta with mahā meaning great and vākya, a sentence. Most commonly, Mahāvākyas are considered four in number, Like other Mahāvākyas, it also explains the unity of Brahman and Atman, which is the basic principle of Advaita Vedanta. Tat Tvam Asi (तत् त्वम् असि) - traditionally rendered as "That Thou Art" (that you are), (Chandogya Upanishad 6.8.7 of the Sama Veda, with tat in Ch.U.6.8.7 referring to sat, "the Existent"); alternatively translated as "That's how [thus] you are," with tat in Ch.U.6.12.3 referring to "the very nature of all existence as permeated by [the finest essence]" Aham Brahmāsmi (अहम् ब्रह्मास्मि) - "I am Brahman", or "I am Divine" (Brihadaranyaka Upanishad 1.4.10 of the Yajur Veda) Prajnanam Brahma (प्रज्ञानम् ब्रह्म) - "Prajñāna is Brahman", or "Brahman is Prajñāna" (Aitareya Upanishad 3.3 of the Rig Veda) Ayam Atma Brahma (अयम् आत्मा ब्रह्म) - "This Self (Atman) is Brahman" (Mandukya Upanishad 1.2 of the Atharva Veda) Those statements are interpreted as supporting the insight that the individual self (jiva) which appears as a separate existence, is in essence (atman) part and manifestation of the whole (Brahman). The four principal Mahavakyas Though there are many Mahavakyas, four of them, one from each of the four Vedas, are often mentioned as "the Mahavakyas". Other Mahavakyas are: ekam evadvitiyam brahma - Brahman is one, without a second (Chāndogya Upaniṣad) so 'ham - I am that (Isha Upanishad) sarvam khalvidam brahma - All of this is brahman (Chāndogya Upaniṣad 3.14.1) etad vai tat - This, verily, is That (Katha Upanishad) People who are initiated into sannyasa in Advaita Vedanta are being taught the four [principal] mahavakyas as four mantras, "to attain this highest of states in which the individual self dissolves inseparably in Brahman". According to the Advaita Vedanta tradition, the four Upanishadic statements indicate the real identity of the individual (jivatman) as sat (the Existent), Brahman, consciousness. According to the Vedanta-tradition, the subject matter and the essence of all Upanishads are the same, and all the Upanishadic Mahavakyas express this one universal message in the form of terse and concise statements. In later Sanskrit usage, the term mahāvākya came to mean "discourse", and specifically, discourse on a philosophically lofty topic. Tat Tvam Asi Chandogya Upanishad 6.8.7, in the dialogue between Uddalaka and his son Śvetaketu.