When two orders are placed simultaneously, one to buy and one to sell, and the execution of one order results in the automatic cancellation of the other, it is known as an "either or" order. This type of order is commonly used in the financial markets to manage risk and protect against potential losses. It allows for a quick response to market changes and ensures that only one order is executed at a time. In other words, it's a way to play it safe in the fast-paced world of finance.