The etymological foundations of "Om" are repeatedly discussed in the oldest layers of the Vedantic texts (the early Upanishads). The Aitareya Brahmana of Rig Veda, in section 5.32, for example suggests that the three phonetic components of "Oṃ" ("a" + "u" + "ṃ") correspond to the three stages of cosmic creation, and when it is read or said, it celebrates the creative powers of the universe. The Brahmana layer of Vedic texts equate "Om" with "Bhur-bhuvah-Svah", the latter symbolizing "the whole Veda". They offer various shades of meaning to "Om", such as it being "the universe beyond the sun", or that which is "mysterious and inexhaustible", or "the infinite language, the infinite knowledge", or "essence of breath, life, everything that exists", or that "with which one is liberated". The Sama Veda, the poetical Veda, orthographically maps "Om" to the audible, the musical truths in its numerous variations ("Oum", "Aum", "Ovā Ovā Ovā Um", etc.) and then attempts to extract musical meters from it.