What is the meaning of democracy? How has it been defined in the past and in the present?
Democracy means power to the people (Demos= people and Kratos=power in Greek)
Democracy is a philosophical concept and therefore it is hard to give it a definite definition. For instance French Philosopher Alain said that democracy was defined by the ability of the people to "control power", not to elect. Therefore our definition nowadays does not correspond to this philosophical concept, indeed we now regard democracy as being defined by universal sufrage(this is why we praise the Civil Rights in the USA or the suffragettes) and this is how we dismiss a certain number of so-called democracies in the past which I am about to expose.
During Classical Greece democracy had a far different meaning, Athens is remembered to be demoratic but it would not be considered democratic in today's standards. Indeed women did not have the right to vote, only citizens could vote(sons of citizens and ofdaughters of citizens) slavery was legal and was the base of the economy.
After the French Revolution the concept of Democracy, Robespierre tried to introduce form of universal suffrage but he was executed in July 1794, his death marked the end of the Terror. Universal male suffrage was introduced only in 1848.
Despite their respective revolutions, Great Britain and the USA became democracies quite late. Great Britain did have universal male suffrage until 1884-1885 and women were enfranchised in 1918(they had to be thirty to be able vote except if they had a college degree until 1928). Universal White male suffrage was introduced by Andrew Jackson but women were given the right to vote in 1920(19th amendment) and Blacks could not vote until the 1960s especially in the South because of the Jim Crow laws(Segregation).
The concept of democracy evolved through time, it comes from classical Greece, it existed also in Ancient Rome(similar flaws than the Athenian system with slavery notably) and it was revived by the Enlightment in the eighteenth century.
The Bills of Rights in both Great Britain and the USA guaranteed basic rights and were not formally democratic in essence. Great Britain was made a Constitutional Monarchy whereas the USA was made a Constitutional Republic, it was representative since the Founding Fathers were resentful toward direct democracy. For instance Senators were elected by State Legislature until 1913(17th amendment).
We know that some democracies were phony, for instance the Popular Democracies in Eastern Europe. Democracies can be direct(like in Switzerland or representative(France, UK, USA). In Switzerland referendums are organized frequently on political issues.
Yet nobody could describe any country as a perfect country ,indeed in Europe more than 80% are issued by the European Commission which is unelected and in the USA, Lobbyists have a tremendous influence over Congress. All those elements demonstrate that Western democracies are far from being authentic. The populist uprising in Europe(Brexit) and in America with Trump's election can be partially explained by these phenomena.