The word yoga means "union" in Sanskrit, the language of ancient India where yoga originated. Yoga can be thought of as the union occurring between the mind, body and spirit. What is commonly referred to as "yoga" in the western world can be more accurately described by the Sanskrit word asana, which refers to the practice of physical postures or poses. Asana is only one of the eight "limbs" of yoga, the others are more concerned with mental and spiritual well being than physical activity. In the West, however, the words asana and yoga are often used interchangeably.