http://www.investopedia.com/terms/c/capitalism.asp
What is 'Capitalism'
Capitalism is an economic system in which capital goods are owned by private individuals or businesses. The production of goods and services is based on supply and demand in the general market (market economy), rather than through central planning (planned economy or command economy). The purest form of capitalism is free market or laissez-faire capitalism, in which private individuals are completely unrestrained in determining where to invest, what to produce or sell, and at which prices to exchange goods and services, operating without check or controls. Most modern countries practice a mixed capitalist system of some sort that includes government regulation of business and industry.
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Voluntary trade is the mechanism that drives activity in a capitalist system. The owners of resources compete with one another over consumers, who in turn compete with other consumers over goods and services. All of this activity is built into the price system, which balances supply and demand to coordinate the distribution of resources.
A capitalist earns the highest profit by using capital goods most efficiently while producing the highest-value good or service. In this system, value is transmitted through those prices at which another individual voluntarily purchases the capitalist's good or service. Profits are an indication that less valuable inputs have been transformed into more valuable outputs. By contrast, the capitalist suffers losses when capital resources are not used efficiently and instead create less valuable outputs.
What's the Difference between Free Enterprise and Capitalism?
Capitalism and free enterprise are often seen as synonymous. In truth, they are closely related yet distinct terms with overlapping features. It is possible to have a capitalist economy without complete free enterprise, and possible to have a free market without capitalism.
Any economy is capitalist as long as the factors of production are controlled by private individuals. However, a capitalist system can still be regulated by government laws and the profits of capitalist endeavors can still be taxed heavily.
"Free enterprise" can roughly be translated to mean economic exchanges free of coercive government influence. Although unlikely, it is possible to conceive of a system where voluntary individuals always trade in a way that is not capitalistic. Private property rights still exist in a free enterprise system, although private property may be voluntarily treated as communal without government mandate. Many Native American tribes existed with elements of these arrangements.
If accumulation, ownership and profiting from capital is the central principle of capitalism, then freedom from state coercion is the central principle of free enterprise.