The phrase "buy or sell" is commonly used in financial contexts to refer to the act of either purchasing an asset (such as a stock, bond, or commodity) with the intent to resell it at a higher price, or selling an asset that one already owns. This can be done through various markets and exchanges where people come together to buy and sell assets in order to make profits. The phrase is often used as shorthand for any type of transaction involving the exchange of goods or services, regardless of whether it involves buying or selling.