v.
1. tr. show evidence of (feelings etc.).
2 tr. describe and explain (a scientific proposition, machine, etc.) by experiment, practical use, etc.
3 tr. a logically prove the truth of. b be proof of the existence of.
4 intr. take part in or organize a public demonstration.
5 intr. act as a demonstrator.
Etymology: L demonstrare (as DE-, monstrare show)