Om

The Om symbol has many interpretations. It has a different meaning from person to person and religion to religion. Om is a mantra, originally in Hindu, that has been used in Indian religions. 

In Hindu, they believe that "Om" is the original vibration and sound as creation began. It is thought to be the manifestation of God. They believe he first created sound then built the universe. Everything that exists and that will exist is symbolized by the symbol. Om is a root sound the world is built on and held together by. Everything vibrates if you listen close enough and that vibration is 'Om'. 

The symbol is composed of three letters: aa, uu, and ma (AUM). It represents three Hindu deities Brahma the creator, Vishnu the preserver, and Shiva the destroyer. It has also been used to symbolize triads: [mind, body, and spirit] [past, present, and future] [earth atmosphere, and heaven]. 

Above there is a diagram with the four states of consciousness in Hinduism.  Wakefulness is symbolized by the lower half of the 3 like letter. Wakefulness is when we turn our consciousness outward and use our senses to interpret the world. It is large portion of the symbol because this is where we spend the majority of our time. The upper half of the 3 is dedicated to deep sleep. This is when we are considered unconscious. We are not dreaming nor wanting anything from the world in this state. The middle outward curve represents a dreaming state, between being awake and deep sleep. The forth state is symbolized by the dot. This when our attention is neither outward nor inward. This is the 'absolute', the ultimate calm and peace we hope to achieve. The semi circle underneath the dot symbolizes, maya - the illusion, the idea of a translucent barrier between the states of consciousness and the absolute. 

People chant this manta to bring them internal peace. It's to help you tune into the world, your core, and your spirituality. It is said at the beginning and ending of Hindu prayers. It is also used in Yoga as a way to help meditate. For myself, 'Om' helps be remember to be calm and focus inward about what truly matters. Reading about the symbol and understanding its many meanings is only one way to grasp the complexity of Om. Try humming Om right now, and see how it feels.