Fascism is a type of governmental system that is ruled by a central dictator. It is marked by "stringent socioeconomic controls, suppression of the opposition through terror and censorship, and typically a policy of belligerent nationalism and racism."

"Fascism tends to include a belief in the supremacy of one national or ethnic group, a contempt for democracy, an insistence on obedience to a powerful leader, and a strong demagogic approach."

Examples of fascist rulers would include Mussolini and Hitler.

Fascism is a dictatorial system of government, coupled with nationalistic fervor usually related to an socio-ethnic group, and supported by nationalistic social capitalism. The emphasis on capitalism is what most differentiates it from communism.
Both fascism and communism are socialist systems.
The dictatorship is what differentiates socialist fascism from democratic socialism.

Fascism is a government philosophy based on nationalism and a single dictatorial leader, it does not have a clear economic philosophy but tends to refute both communism and capitalism in most fascist countries.

It is in contrast to other forms of government, such as:

Democracy which is a form of government in which the people directly decide on matters. In the United States it is still used in some New England communities either with or in-place of a Town/City Council. Its roots are in greek city-states.

Republics (Representative Democracy) which is a government which is governed by elected officials.

Monarchy which is ruled by a soveriegn ruler that ascended by birthright (in some cases supposedly divine right). While monarchies still exist in name, most are constitutional monarchies that function as a republic in everything but name.

Socialism is a form of government where wealth is distributed equally amunst the people. There is no prevailing government structure with socialism, it can range from democracies to dictatorships.

Communism is a branch of Socialism, but instead of distributing wealth evenly, the government takes ownership of everything and rations out goods and services directly. Communist governments are usually single party autocracies or oligarchies.

Fascism tends to be considered the far right of the political scale, opposite socialism and communism considered to be on the far-left. Fasicm is almost always dictatorial (sometimes an oligarchy though) but not all dictators are fascist.

Fascism is when (in context of a Government) one person has all power, the principles of it, are generally towards nationalism and rascism. An example of this could be Hitler.