In an auction, items are sold without price tags––whoever bids the highest gets to buy it, whether it’s a painting, a car, or a set of old dishes.
You can hold an auction, or auction something. You might have seen auction scenes in classy old movies where the characters bid on paintings by politely raising their hands as the auctioneer calls out a price. Auctions aren’t always high-fallutin’, though. Many cities auction off cars they’ve confiscated from drug dealers or thieves.