The OM symbol, also called Aum, is a sacred symbol and sound in religions such as Hinduism and Buddhism.  It is believed to represent the sound of the universe and symbolizes peace, spiritual connection, and unity of mind, body, and spirit.  Many people chant "OM" during meditation and yoga to help create a sense of calmness and focus.
 
Meditation is a practice that helps calm the mind and improve focus, awareness, and inner peace.  It often involves deep breathing, mindfulness, or concentrating on a sound, thought, or activity to reduce stress and promote relaxation.