What is a loop of rope designed as a restraint to be thrown around a target called?

A lasso, also called lariat, riata, or reata (all from Castilian, la reata 're-tied rope'), 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 American cowboy.

The word is also a verb; to lasso is to throw the loop of rope around something. Although the tool has several proper names, such terms are rarely employed by those who actually use it; nearly all cowboys simply call it a "rope," and the use of such "roping." To most cowboys, the use of other terms — especially "lasso" — identifies the user as a layman.