> Monopoly is if one corporation owns an entire market.
This isn't quite right. Traditionally for a company to be a monopoly it isn't even required it control a majority of the market. It has more to do with the company being in a privileged circumstance in a market and explicitly using that privilege to bolster themselves or suppress competition in the same or related markets.
An example is Microsoft with Netscape. Microsoft was sued with anti-trust laws not because IE or Windows owned the entire market, but because Windows gave Microsoft a privileged place in the web-browser market that they abused.
