Definition from Wiktionary, the free dictionary
- A line of dialog that suggests new plot lines but that mean little or nothing in the current context.
- As the film opens, a martial-drum-dominated version of the "Star Wars" theme and the inevitable bottom-to-top print crawl inform us that the Clone Wars, a conflict that originated as a throwaway line in the original 1977 film... http://www.nysun.com/arts/star-wars-clone-wars-painted-in-the-stars/83922/
- I was intrigued by the exchange in one of the opening scenes where the Warden says to Snake: "You flew the wing-five over Leningrad, didn't you?" It turns out to be just a throwaway line, but for a moment it worked like the best SF, where a casual reference can imply a lot. http://project.cyberpunk.ru/idb/gibson_interview.html