A market in which buyers enter competitive bids and sellers enter competitive offers at the same time. The price a stock is traded represents the highest price that a buyer is willing to pay and
the lowest price that a seller is willing to sell at. Matching bids and offers are then paired together and the orders are executed. 

 
Investopedia explains 'Auction Market'

The New York Stock Exchange (NYSE) is an example of an auction market. Auction markets differ from over the counter where trades are negotiated. For example, 4 buyers want to buy a share of XYZ and make the following bids: $10.00, 10.02, 10.03 and $10.06. Conversely, there are 4 sellers that desire to sell XYZ and they submitted offers to sell their shares at the following prices: $10.06, 10.09, 10.12 and $10.13. In this scenario, the individuals that made bids/offers for XYZ at $10.06 will have their orders executed. All remaining orders will not immediately be executed and the current price of XYZ will then be $10.06.

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