A written auction contract is referred to as:

A written auction contract is referred to as "expressed." This terminology signifies that the terms and conditions of the contract are explicitly stated in writing, making them clear and unambiguous to all parties involved. An expressed contract outlines the specific details of the auction process, including the rights and obligations of the auctioneer and the seller, and it serves as a formal agreement that can be legally enforced.

In contrast, implied contracts arise from the actions or circumstances of the parties rather than from written or spoken words. Verbal contracts are those that are agreed upon through oral communication, which can often lead to misunderstandings or disputes since they lack the clarity and permanence of a written document. The term "informed" does not accurately describe the nature of a contract and is not a recognized classification in contract law.

Hence, the characterization of a written auction contract as "expressed" is accurate and highlights the importance of having a clear, documented agreement in place for the auction process.