A demonstration is when someone shows how something works or proves that something is true by doing it in front of others. When a science teacher demonstrates how a volcano erupts by mixing baking soda and vinegar, she's showing the class exactly what happens rather than just describing it. When a chef demonstrates how to fold dough for croissants, viewers can watch each step unfold.

The word also describes a public gathering where people march or protest together to show support for a cause or opposition to something they believe is wrong. These demonstrations (sometimes called demos or protests) let citizens express their views visibly and publicly. Throughout history, peaceful demonstrations have been a powerful way for people to demand change, from workers demonstrating for safer conditions to students demonstrating for better school funding.

In both meanings, a demonstration involves making something visible and clear. Whether you're demonstrating a math technique on the board or joining a demonstration for a cause you believe in, you're making your point through action rather than just words. The person showing how something works is called a demonstrator, which is also a word for someone participating in a public protest demonstration.