Terminal can be understood as the last link in the whole economic production activities, sales, which can be consumers or producers. For example, your materials are aimed at producers. If your product is sold to your final customer, it is terminal sales. But now many people are speculating on houses. You can buy one apartment, but you can also buy n apartments. As long as you have money, you can resell it and get considerable speculative futures income. At that time, the process of that person selling the house to you was not a terminal sale. You sold them because you didn't really need so many houses to live in.