There are different instruments of communication available for a human being: verbal and nonverbal communication, like gesture.
Gesture is defined as visible bodily action by which meaning is represented. ([Kendon 1983]). This includes manual gestures, movements of the whole body, head movements (e.g. nodding) and facial movements (e.g. raising your eyebrows). In other studies gesture is referred to as "body language" or "kinesics").
Some useful links on gesture: