A lasso (from Latin laqueus, meaning noose) is a long, strong thong of leather or rope with a slipknot forming a noose at one end. In Hispanic countries it is called a lariat and is usually a braided rather than a twisted cord.
Lassos are used by cowboys, ranchers, and hunters. The lasso loop is made large enough to slip over the head of the animal to be caught and is then twirled over the thrower's head and cast so that it will open up and settle over the animal. A strain on the held end tightens the noose; further strain will force the captured animal to stop.
A well-trained horse will maintain the strain on a lasso attached to its saddle's horn, so that the rider can dismount and truss the animal for branding. An expert can lasso a galloping horse, its rider, or both, and such roping is usually a feature of the modern rodeo. A South American version of the lasso has a short T-section at the end of the thong with weights on each end of the crosspiece. This lasso is thrown in such a way that the cross-piece entangles the legs or neck of the animal to be captured.
Will Rogers popularized the lasso with his rope-twirling acts which he began in 1905. Lassos also have been used in military actions in South America and against French sentinels by some of the semibarbarous tribes which Russia had pressed into her armies during the Crimean War (1854-1856). A thrown lasso makes no sound and can be tightened quickly enough to prevent the shouting of an alarm.