A more thorough explanation:

Definition: In diem addictio is a legal term from Roman law that refers to a clause in a contract of sale. It allows the parties involved to terminate the contract if the seller receives a better offer within a specified period. It can also refer to postponement to a date.

Example: Let's say that John wants to sell his car to Jane for $10,000. They agree to a contract that includes an in diem addictio clause that states that if John receives a better offer within the next 7 days, he can terminate the contract with Jane. On the 5th day, John receives an offer for $12,000 from another buyer. He decides to terminate the contract with Jane and sell the car to the other buyer.

This example illustrates how the in diem addictio clause allows the seller to terminate the contract if they receive a better offer within a specified period.