Find any definition of "monopoly" and it should be pretty clear that it's not merely marketshare but the active manipulation of markets and market conditions to produce that marketshare.
> A monopoly is a market in which one person or company is the only supplier of a particular good or service. A monopoly is characterized by a lack of economic competition to produce a particular thing, a lack of viable substitute goods, and the possibility of a high monopoly price well above the seller's marginal cost that leads to a high monopoly profit.