Om (ôm) [key], [Skt., = yes, so be it] for Hindus and Buddhists, a mystic word or mantra. Om is regarded as the syllable of the supreme Reality and is sometimes called "the mother of mantras." It is often found at the beginning of prayers, mantras, and scriptures as a word of invocation and adoration. In Hinduism its three Sanskrit phonemes (transliterated a, u, and m ) symbolize the triad of Brahma the creator, Vishnu the preserver, and Shiva the destroyer, or the three levels of consciousness: waking, dreaming, and deep sleep. In Buddhism it is often understood as symbolizing the true "empty" character of reality, as that truth has been communicated by various historical Buddhas, celestial Buddhas, and, directly, by the true character of reality itself (see sunyata).