People use it to mean different things.
A democracy is a system whereby those in power are elected by the populace. (representative democracy)
A democracy is a system whereby political power is allocated to the people in general, and not to particular classes of people (the basis for socialist dictatorships pretending to be democratic)
A democracy is a system whereby poeple are selected by lottery to exercise power on behalf of the state (the jury system, athenian democracy, sortition)
The last is Montesquieu’s definition.
