These seem good: https://www.wordnik.com/words/capitalism

from The American Heritage® Dictionary of the English Language, 5th Edition.

noun An economic system in which the means of production and distribution are privately or corporately owned and development occurs through the accumulation and reinvestment of profits gained in a free market.

from The Century Dictionary.

noun The state of having capital or property; possession of capital.
noun The concentration or massing of capital in the hands of a few; also, the power or influence of large or combined capital.

from the GNU version of the Collaborative International Dictionary of English.

noun An economic system based on predominantly private (individual or corporate) investment in and ownership of the means of production, distribution, and exchange of goods and wealth; contrasted with socialism or especially communism, in which the state has the predominant role in the economy.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

noun politics, uncountable a socio-economic system based on private property rights, including the private ownership of resources or capital, with economic decisions made largely through the operation of a market unregulated by the state.
noun economics, uncountable a socio-economic system based on the abstraction of resources into the form of privately-owned capital, with economic decisions made largely through the operation of a market unregulated by the state.
noun countable a specific variation or implementation of either such socio-economic system.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

noun an economic system based on private ownership of capital