In cowboy slang, "through" is used to mean "finished" or "completed." It is often used in the phrase "all through," which means "completely finished." For example, a cowboy might say, "I'm all through with this job," to indicate that he is done with it. The word "through" can also be used to refer to a person who has died. In this sense, it is similar to the word "gone." For example, a cowboy might say, "He's gone through," to indicate that someone has died.