Adapted from an article on Wikipedia.
Namaste is a Sanskrit word that is a common spoken greeting in India and other South Asian countries. Literally, it means "I bow to you." When spoken to another person, it is commonly accompanied by a slight bow made with hands pressed together in front of the chest, palms touching and fingers pointed upward. The word and accompanying gesture express deep respect. The gesture can be performed wordlessly and carry the same meaning. Namaste is also used as a friendly greeting in written communication.
In everyday life, namaste is not necessarily a religious gesture. However, many consider it a spiritual one, recognizing a common divinity within the other person.
When greeting a peer, a namaste with the hands in front of the chest and a slight bow is considered polite. To indicate deep respect, one may place the hands in front of the forehead. Reverence for a god or the holiest of persons may be indicated by placing the hands together completely above the head. In the gesture of bringing both hands together with palms touching, one hand represents the higher, spiritual nature, while the other represents the worldly self. The person making the gesture is attempting to rise above their differences with others and connect with the other person to whom they bow. The bow is symbolic of love and respect.
In recent times, and more globally, the term namaste has come to be associated with yoga and spiritual meditation. In this context, it takes on a number of meanings tied to the spiritual origins of the word. It may be expressed as "I honor the Light/Spirit/Divine in you which is also in me," or "All that is best and highest in me greets/salutes all that is best and highest in you."