What is a lariat?

The same thing as a lasso, essentially, but lariat is considered the more technical term. It's a rope, often but not always made of rawhide, that is used to capture stock. (Usually cattle, but it's also possible - if tricky - to rope horses. Horses are more likely to see the rope coming and dodge). When not in use, a lariat is generally hung from the saddle horn or otherwise secured to the saddle.