A lasso or lazo, also called reata or la reata in Mexico, and in the United States, riata or lariat (from Mexican Spanish lasso for roping cattle), is a loop of rope designed as a restraint to be thrown around a target and tightened when pulled. It is a well-known tool of the Mexican and South American cowboys, which was then adopted from the Mexicans by the cowboys of the United States. The word is also a verb; to lasso is to throw the loop of rope around something.

Source: Wikipedia