Revolution is a directly democratic and spontaneous overthrow of an unpopular dictatorship, political system or government by way of a popularly-backed mass movement rather than electoral or reformist means favoured by indirect, bourgeois democracy.
In the Marxist context, it pertains specifically to the overthrow of capitalist planning and social class structure by a socialist movement in order to create a worker's state. Revolution is direct democracy in action because its occurance requires the will and consent of the majority.
Social and political revolutions
A political revolution is replacement of an unpopular and outmoded structure of government by one with popular support that reflects underlying economic relationships. A revolution which has massive public support may not be violent as the previous rulers will recognise the futility of resistance. The Indian independence movement is an example. However, often there may be violent resistance, and in extreme cases, civil war may result. Revolutionary war may result in vast changes in power structures that can often result in further, institutionalised, violence, as in the Russian and French revolutions. A political revolution is the forcible replacement of one set of rulers with another (as happened in France and Russia), while a social revolution is the fundamental change in the social structure of a society, such as the Protestant Reformation or the Renaissance. However, blurring the line between these two categories, most political revolutions have basic philosophical or social underpinnings which drive the revolution. The most common of these underpinnings in the modern world have been liberal revolutions and Communist revolutions. In contrast, a coup d'etat often seeks to change nothing more than the current ruler.
Some political philosophers regard revolutions as the means of achieving their goals. Most anarchists advocate social revolution as the means of breaking down the structures of government and replacing them with nonhierarchal institutions, while Marxist communists take revolution to be one strategy, possibly accompanied by the use of electoral politics to take over, rather than overthrow, the institution of government, their aim being to create a communist society.
Social and political revolutions are often "institutionalized" when the ideas, slogans, and personalities of the revolution continue to play a prominent role in a country's political culture, long after the revolution's end. As mentioned, socialist nations regularly institutionalize their revolutions to legitimize the actions of their governments. Some capitalist nations, like the United States, France, or Mexico also have institutionalized revolutions, and continue to celebrate the memory of their revolutionary past through holidays, artwork, songs, and other venues.