Om (?), interj. & n. [Also Aum,
Um. Skr. om.]
A mystic syllable or
ejaculation used by Hindus and Buddhists in religious rites, -- orig.
among the Hindus an exclamation of assent, like Amen, then an
invocation, and later a symbol of the trinity formed by Vishnu, Siva,
and Brahma. -- Om mani padme hum, a sacred
formula of buddhism (esp. of the Lamaists) translated "O, the Jewel in
the Lotus, Amen," and referring to Amitabha, who is commonly
represented as standing or sitting within a lotus.
© Webster 1913.