https://en.wikipedia.org/wiki/Monopoly

> A monopoly (from Greek μόνος, mónos, 'single, alone' and πωλεῖν, pōleîn, 'to sell') exists when a specific person or enterprise is the only supplier of a particular commodity. This contrasts with a monopsony which relates to a single entity's control of a market to purchase a good or service, and with oligopoly and duopoly which consists of a few sellers dominating a market.[1] Monopolies are thus characterized by a lack of economic competition to produce the good or service, 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.[2]

For example, almost everyone can get their medication at Costco, Walmart, CVS, and Walgreens.