Democracy is a system of government which recognizes the entire population as all having the right to participate in the decision making process. The people have the ability to appoint or dismiss their rulers. The word "democracy" came from an ancient Greek word "demokrati" from the 5th Century BC, which means "people power".
At first, the voting-rights were expanded from a small group of aristocrats to all eligible males who completed compulsory military training. In the 5th century, full citizens in Athens went from 30,000 people to 250,000. All Athenian citizens were free to vote to create laws, a segment could vote on when to go to war, and anyone could speak in the Assembly. This type of government is known as a form of direct democracy. Then democracy spread from the court to political spaces, which was located symbolically right in the centre of the city. In the 4th century (the time of Aristotle), there were hundreds of Greek democracies. In those times, Greek was not a single political entity but there were some 1,500 separate poleis (ancient Greek city-states) scatterred around the Mediterranean and Black Sea shores. So, we can sum up that the democracy is the oldest, the most stable, the most long-lived, but the most radical too.