Non-verbal communication is communication that does not involve a verbal element.

Example
Non-verbal communication includes gestures such as waving or tapping your fingers, eye movements such as winking and rolling, and body movements such as shrugging your shoulders.

In the classroom
Many examples of non-verbal communication are different in different cultures, including body movements, gestures and distance between speakers. It can be interesting and productive to ask learners in a multi-lingual class to compare these.