Capitalism is:

1. an economic system characterized by private ownership of the means of production and free trade, with no government intervention in either.
   The theoretical definition, aka laissez faire, capitalism as ideal or model, like "democracy" or "equality."
   
   
   
2. an economic system characterized by mainly private ownership of the means of production and more or less free trade.
   The descriptive definition, aka the economics definition, a technical operational definition.
   
   
   
3. a resource usage system based on de jure private ownership of the means of production.
   The legal definition, focusing on the legal fiction rather than actual control by government. Used in ideology map.
   
   
   
4. having ownership of capital
   The original definition, used by novelist William Thackeray in 1854, derived from "capitalist."
   
   
   

5. Socialist definitions
   1. an economic system which enables or allows usury, defined as rent, interest, and profit.
   2. an economic system characterized by accumulation of capital in the hands of the few.
   These socialist definitions dating from the 19th century are still used by some leftists.
   
   
   
6. Marxist definitions
   1. an economic system characterized by privately owned means of production for profit.
   2. an economic system where the predominant mode of production involves employment - workers selling their labour power, their ability to work, as an alienated commodity to the owners of capital.
   3. an economic system characterized by employment ("wage slavery") and collusion between wealthy capitalists and the State.
      Marxist definitions, used by many leftists, especially communists.
   
   
   
7. the economic system which currently prevails or historically existed in the US, Germany, Japan, and other "developed" countries.
   The historical definition, aka actually existing capitalism or the naive definition, usually refers to a mixed economy.
   
   
   
8. the economic system of industrial revolution era Britain.
   A British historical definition.
   
   
   
9. rule of workplaces, society, and if there is one, the State, by capitalists (that is, by a relatively small number of people who control investable wealth and the means of production)
   The conspiracy definition, used by Gary Chartier.
   
   
   

Also see: definitions of socialism and a table of characteristics of capitalism.

Sometimes these definitions are combined in a contradictory manner. (1) and (7) are often combined in a package deal. Cf: Roderick Long's essay Rothbard's "Left and Right": Forty Years Later.