Learner's definition of DEMONSTRATION
1 : an act of showing someone how something is used or done
I went to a sculpture demonstration last weekend.
One of the instructors gave/did a demonstration of how to prune a tree.
Would you mind giving us a demonstration so that we can see how the machine works?
[noncount] — sometimes used before another noun
2 : an event in which people gather together in order to show that they support or oppose something or someone
Students took part in several nonviolent/peaceful demonstrations against the government.
demonstrations against the war = antiwar demonstrations
demonstrations for women's rights
3 : an act of showing or proving something
[count] — often + of
a demonstration of their power/loyalty/skill
a demonstration of grief/bravery
They brought some bread to share as a demonstration [=token] of goodwill.