The term 'USE A LASSO ON' can be solved by the word 'ROPE', which is a four letter word. A lasso is a loop of ROPE that is used to catch animals or objects, and it is typically thrown from a distance. The lasso is a tool that has been used for centuries by cowboys and ranchers to capture livestock. It is also used in some sports, such as roping, where competitors must use a lasso to capture a calf or steer.