An auctioneer is a person who manages an auction, or a public sale at which people can bid on items. It's exciting to win the bidding at an auction and hear the auctioneer shout, "Sold!"
It's the job of an auctioneer to organize the goods for sale at an auction, as well as to oversee the bidding, often encouraging bidders to compete with each other to drive the price up. Some auctioneers call out items and prices in a distinctive, rapid, sing-song voice. Auctioneer comes from auction, which has a Latin root: auctionem, "increasing sale or public sale," from augere, "to increase."