Economic Definition of public good. Defined.
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Term public good Definition: A good that's difficult to keep nonpayers from consuming (excludability), and use of the good by one person doesn't prevent use by others (rival consumption). Examples include national defense, a clean environment, and any fourth of July fireworks display. Public goods are invariably provided by government because there's no way a private business can profitably produce them. Private businesses can't sell public goods in markets, because they can't charge a price and keep nonpaying people away. Moreover, businesses shouldn't charge a price, because there's no opportunity cost for extra consumers. For efficiency, government needs to pay for public goods through taxes.