A broad interpretation is:
Monopoly – the exclusive right of manufacturing, trading and other activities belonging to the same person, a certain group of persons or the state. If such right belongs to the firm, this means that it has monopoly power. Monopoly power gives the firm the ability to influence the price of the goods. The degree of monopoly power depends on many factors, but mainly from the share of firms in total sectoral proposals and the availability of substitute products.
If the firm is the sole seller of goods that has no close substitutes, the consumer is faced with a pure monopoly.
Pure monopoly is a type of market structure where the firm is the sole manufacturer of any product that has no analogues.
You should not identify the concept of "pure monopoly" and "monopoly power": it's not the same thing. To possess monopoly power, the firm is not required to be a pure monopolist.