A monopoly has at least one of these five characteristics:
Profit maximizer: monopolists will choose the price or output to maximise profits at where MC=MR. This output will be somewhere over the price range, where demand is price elastic. If the total revenue is higher than total costs, the monopolists will make abnormal profits.
Price maker: Decides the price of the good or product to be sold, but does so by determining the quantity in order to demand the price desired by the firm.
High barriers to entry: Other sellers are unable to enter the market of the monopoly.
Single seller: In a monopoly, there is one seller of the good, who produces all the output.[6] Therefore, the whole market is being served by a single company, and for practical purposes, the company is the same as the industry.
Price discrimination: A monopolist can change the price or quantity of the product. They sell higher quantities at a lower price in a very elastic market, and sell lower quantities at a higher price in a less elastic market.
Just so we have a definition of a monopoly.