“Monopoly is the situation where a single company sells a particular product or service. There are few products or services that are available only with a single seller. Monopoly is simply defined as absence of competition.
It could be because the company has got the product patented. There could also be a monopoly if the company is technologically so advanced that it lacks competitors or it could be simply ruling the market due to the superior quality of its goods or services. There are also natural monopolies. For example, if a particular natural resource is found in a particular area. That naturally makes some more privileged than others for that particular business.