The word Om (also called Pranava) is comprised of three constituent sounds: “ah”, “u”, and “m”. These sounds mean respectively the Creator, Preserver, and Dissolver. In Sanskrit the sounds of vowels “a” and “u” combined together produce the sound that is equal to “o”. Therefore “(a + u) + m = o + m = Om. These three sounds imply, among many other things, the three Vedas and three divisions of the universe — the past, the present, and the future.  Each consistent sound in Om represents a large set of names of God. Therefore, by reciting Om we meditate upon many different attributes, manifestations, and powers of God. Om is considered the best name of God.