A Monopoly is the only firm in a particular market. At the other end of the spectrum is a perfectly competitive firm. Most industries are somewhere in between pure monopoly and perfect competition. The essential different between the two is the degree to which a firm can control prices. In any industry, the market price is determined my the intersection of supply and demand for the product.
Supply is the sum of all firms' supply curves.
If market supply decreases, the price of the product rises. No matter if the industry is a monopoly or if there are lots of firms, the market cannot be forced to pay a higher price for less goods. The demand curve must always be obeyed. If the price is raised, some will continue to buy, but some will no longer buy the product. Their decision about how much to produce has no noticeable affect on market quantity and prices.