Which of these is a by-product or incidental result of a larger project?

In media, a spin-off (or spinoff) is a radio program, television program, video game, film, or any narrative work, derived from already existing works that focus on more details and different aspects from the original work (e.g. particular topics, characters or events).

One of the earliest spin-offs of the modern media era, if not the first, happened in 1941 when the supporting character Throckmorton P. Gildersleeve from the old time radio comedy show Fibber McGee and Molly became the star of his own program The Great Gildersleeve (1941–1957).

In genre fiction, the term parallels the usage in television; it is usually meant to indicate a substantial change in narrative viewpoint and activity from that (previous) storyline based on the activities of the series' principal protagonist and so is a shift to that action and overall narrative thread of some other protagonist, which now becomes the central or main thread (storyline) of the new sub-series. The new protagonist generally appears first as a minor or supporting character in the main story line within a given milieu, and it is very common for the previous protagonist to have a supporting or cameo role, at the least as a historical mention, in the new sub-series. Spin offs sometimes generate their own spin-offs, leaving the new show in its own series only vaguely connected to the original series.