A gesture is a form of nonverbal means of communication, which usually involve the movement of the hands, fingers, eyes, head, face etc.
However, in this context, the type of gesture used is the "EMBLEM GESTURE." Emblems are nonverbal signs that can commonly be interpreted directly into words. Most people within a particular community or nation understands their meaning easily. A good example is a circle with the thumb and forefinger to communicate or to say that everything is okay, although in America this is a common gesture, however, in another culture, this could mean zero or something different entirely.