Body language is a form of nonverbal communication that conveys messages without words through facial expressions, gestures, posture, and eye contact. It varies across cultures, with some gestures having different or opposite meanings. For example, in Japan a circle formed with the thumb and index finger means zero, while in other countries it means okay or money. Bowing is commonly used as a greeting in Japan. Cultural differences in body language and perceptions of physical space must be considered to avoid unintended rudeness or disrespect.