Definition: This is when one company controls the market for a certain product, there is no competition.
Example: Standard Oil Company
ANSWER: Monopoly.
A monopoly is when one company or entity controls an entire share of a market. For example, if Apple became the only company you could buy a cell phone from, this would make Apple a monopoly. Monopolies can hurt the American economy, as a business with no competition can essentially charge whatever they want for a good or service since there will be no business who will offer a better prices.