Definition from Wiktionary, the free dictionary
Alternative forms 
spin-off (plural spin-offs)
- An incidental benefit or unexpected pay-off.
- Space research often provides a spin-off for everyday technology.
- A fictional work where the protagonist was introduced in a preceding work or at least shares the same equivalent setting, often in a different aspect.
- "Frasier" was a spin-off from the sitcom "Cheers".
- The formation of a subsidiary company that continues the operations of part of the parent company; the company so formed.
See also 
- (literature): subseries