the.com/demonstration
Proof you can perform, whether in a lab, a courtroom, or the streets.
means An act of showing something clearly — a fact, a method, or a collective opinion — through visible action.
from From Latin demonstrare, to point out fully, fusing de- (completely) with monstrare, to show — sibling of monster, the thing originally shown as a warning.
Math meaningIn proofs, it means rigorous logical demonstration.
Protest sensePublic marches became demonstrations only in the 1800s.
Monster cousinBoth descend from showing — one warned, one explains.