Acupuncture (from Lat. acus, "neele", and pungere, "prick") or in Standard Mandarin, zhe-n bia-n (a related word, zhe-n jiu, refers to acupuncture together with moxibustion) is a technique of inserting and manipulating fine filiform needles into specific points on the body with the aim of relieving pain and for therapeutic purposes. According to acupuncture theory, these acupuncture points lie along meridians along which qi, a kind of vital energy, is said to flow. There is no generally-accepted anatomical or histological basis for these concepts, and modern acupuncturists tend to view them in functional rather than structural terms, (viz. as a useful metaphor in guiding evaluation and care of patients). Acupuncture is thought to have originated in China and is most commonly associated with Traditional Chinese Medicine (TCM). Different types of acupuncture (Classical Chinese, Japanese, Tibetan, and Korean acupuncture) are practiced and taught throughout the world.