Piezoelectric materials are substances that can generate electric charges when mechanical stress or pressure is applied to them. In other words, they can convert physical pressure or movement into electrical energy. Full definition
The use of piezoelectric materials was their original innovation, and it allowed them to simultaneously measure the flexing and the rotation of the teeter - totter beam. (sciencedaily.com)
For it to operate underwater, the team used piezoelectric materials in its construction so that it will be powered by the bobbing of the waves. (treehugger.com)
The Greek word piezein means «to squeeze or press,» and piezoelectric materials generate a charge when squeezed or deformed or smashed — like smashing two rocks together to produce a flash. (discovermagazine.com)