Amonopoly has seller(s), but perfect competition has seller(s).

A monopoly has "one" seller, but perfect competition has "many" sellers.

"Monopoly" has been gotten from the two Greek words 'Monos' and 'Polus' implies single seller.'Monos' means single and 'Polus' implies sellers, so the word "Monopoly" implies single seller. Monopoly is a market structure in which there is a single firm creating all the yield and there is no nearby substitute of item sold by the monopolist.

As against monopoly market, a perfect competition has expansive number of sellers. Under perfect competition just a solitary item is sold. This implies every one of the sellers sell a similar kind of item to purchasers.