Body language is a form of non-verbal communication that conveys information through physical behaviors like facial expressions, gestures, eye contact, posture, and touch. It includes both intentional movements like gestures as well as unconscious movements that reveal personal feelings, emotions, attitudes, and thoughts. Some key aspects of body language discussed in the document are facial expressions, hand gestures, eye contact, posture, and the use of space between individuals. Mastering body language can improve communication effectiveness and help build stronger first impressions.