Most use the word lasso, instead lariat. Lasso is commonly used as a noun when it is actually a verb. This is one of the easiest ways to spot a greenhorn in the cattle pen. For those who actually use lariat, they refer to it as a rope and it is used when roping something. The difference between a Lariat and a Lasso is not anything more than a mix up of when or how nouns and verbs should be used.