A Walrasian market is a market where orders are grouped and analyzed to determine a clearing price that will determine the market price.
The Walrasian market was developed by Léon Walras to demonstrate that there can be a state of general equilibrium in which there is equal demand and supply in all markets at the same time.
Buyers and sellers have little to say about the final prices of their transactions in the Walrasian market, unlike auction markets where market forces are at work.
In the Walrasian market, buy and sell orders are grouped together and then executed at a specific time, rather than sequentially one after the other.
The NYSE uses a process similar to the Walrasian market before calling to open to determine opening prices.