A market in which only one company may try to dominate and offer products and services to the people. This is a situation just opposite of a proper competitive market that comprises of an infinite number of firms operating independently.
In a purely monopolistic model, the monopoly company is able to refrain output, hike prices and enjoy super-normal profits in the long run.
Pure monopoly markets are extremely rare and impractical, a close impossible in the absence of absolute barriers to entry, such as a ban on competition or sole possession of all natural resources.
Hope this gives you a basic idea!!!