A spin-off is a buzzword for an officially-recognized continuation series utilizing either some or all of the original cast of a series and/or using the same premise and/or set in the same town / country / universe as television series already (or recently) on-air.
Spin-offs are frequently financially driven by the success of a parent series, and extend the marketable life of the series to the point of becoming a saga that spawns a series franchise.
Spin-offs are commonly produced by the same production company / team responsible for the originating series. Spin-offs can generate spin-offs of their own.
Spin-offs can be set in contemporary time relative to its parent, or occur before or after the events of the parent show.
While spin-offs on TV in recent history are commonly science-fiction related, writers such as Norman Lear, Aaron Spelling and Garry Marshall dominated spin-off efforts in the 1970s and 1980s of American television.
Examples
- The Jeffersons, spun from All in the Family
- Stargate Atlantis, spun from Stargate SG-1, spun from the motion picture, Stargate
- Star Trek: Voyager, spun from Star Trek Deep Space Nine, spun from Star Trek: The Next Generation, spun from the original Star Trek series, which spun Star Trek: Enterprise, set 100 years prior to the parent show
- Crusade, spun from Babylon 5
- Caprica a proposed spin-off of the Re-imagined Series, depicts life over 52 years prior to the Re-imagined Series
- Galactica 1980, spun from the 1978 Battlestar Galactica
The Re-imagined Series is, as its name suggests, not a spin-off but a re-imagining that draws elements from a previous show but does not continue the original show's characterizations or storylines.
In contrast, a continuation is a form of spin-off that occurs after a series has ceased production for some time, which usually resumes the original storylines and characters.