A miniseries (also mini-series) is a television show production which tells a single story in a limited number of episodes. The number of episodes is variable; however, they are usually limited to fewer than a whole season (13 weeks).
Before the invention of this term in the USA, such a production was always known as a "serial". The use of the term "miniseries" is still generally limited to North America. Various British television productions dating from the 1950s onwards fit the definition of miniseries, but in Britain these are referred to as "serials".
The term "miniseries" is used to refer to a single finite story told in separately broadcast episodes. Before the term was coined, such a form was always called a "serial", in the same way that a novel appearing in episodes in successive editions of magazines or newspapers is called a serial. Several commentators have offered further qualifications. Leslie Halliwell and Philip Purser argue that miniseries tend to "appear in four to six episodes of various lengths", whilst Stuart Cunningham defines them as, "a limited run program of more than two and less than the 13-part season or half -season block associated with serial or series programming." Francis Wheen states, "Both soap operas and primetime series cannot afford to allow their leading characters to develop, since the shows are made with the intention of running indefinitely. In a miniseries on the other hand, there is a clearly defined beginning, middle, and end, (as in a conventional play or novel) enabling characters to change, mature, or die as the serial proceeds."
None of these qualifications, however, gets to the essential point, which is quite simple. A series is a run of drama shows using the same basic characters and in which each show is a self-contained story. By contrast, a miniseries is not in fact a series of any kind, but a serial in which a single story is serialised in several episodes.
North America 
In North America the format began in 1974 with the Canadian Broadcasting Corporation's The National Dream, featuring Pierre Berton (which aired from 3 March 1974 to 28 April 1974) and the American Broadcasting Company's QB VII, which starred Anthony Hopkins (and which began on 29 April 1974). Following these initial forays, broadcasters used miniseries to bring other books to the screen. Rich Man, Poor Man, based on the novel by Irwin Shaw, was broadcast in 12 one-hour episodes in 1976 by ABC. Alex Haley's Roots in 1977 can fairly be called the first blockbuster success of the format. Its success in the USA was partly due to its schedule: the 12-hour duration was split into eight episodes broadcast on consecutive nights, resulting in a finale with a 71 percent share of the audience and 130 million viewers, which at the time was the highest rated TV program of all time. TV Guide (April 11-April 17, 1987) called 1977's Jesus of Nazareth "the best miniseries of all time" and "unparalleled television".
Miniseries were popular through the 1990s on the Big Three television networks, often as big-budget ratings-grabbing efforts scheduled for sweeps months; however, the use of the format declined quickly after approximately 2000 (coinciding with a similar collapse in producing made-for-TV movies) because of budgetary concerns. The format has made somewhat of a comeback on cable; History, for example, has had some of its greatest successes with miniseries such as America: The Story of Us, Hatfields & McCoys and The Bible.
In British television, the term "miniseries" is almost never used, except in reference to American imports. The term serial is preferred for serialised dramas, which have been a staple of UK television schedules since the early 1950s when serials such as The Quatermass Experiment (1953) established the popularity of the form.
Comic book 
A comic book miniseries (also referred to as a limited series), is a commonly used format of comic book distribution, as it allows creators to tell a single specific story focusing on a character or set of characters, whether that story stands alone (Watchmen), or is heavily interlinked with other events in the same fictional universe (Civil War). Most miniseries is anywhere from two to 12 issues (a story contained in a single issue is termed a one-shot; for a time DC Comics used the term "maxi-series" for a 12-issue miniseries, but this term has been abandoned). 52 was arguably the longest comic book miniseries at the time it was released, running for 52 weekly issues (its publisher, DC Comics, has since used the 52-part weekly series structure twice more). A comic series that does not have a planned endpoint—in other words, one which is not a miniseries—is an ongoing series.
Comic book series intended from the beginning to tell a specific, finite story can become longer still, for example Sandman, which lasted 75 issues, or Cerebus the Aardvark, which ran for 300, a goal creator Dave Sim set for himself fairly early in the series' run, but did not plan from the beginning. These are not considered miniseries, partly because of their sheer size and partly because no fixed number of issues was announced at the outset. Similar to a canceled television series, a series intended to be ongoing, but which is discontinued after a dozen or fewer issues (usually due to poor sales), is not considered a miniseries, though they are sometimes described as such by the publisher after the cancellation is announced.
See also 
- Halliwell, Leslie, and Peter Purser, Halliwell's Television Companion, London: Paladin, 1987
- Stuart Cunningham, "Miniseries", Museum of Broadcast Communication web site