In Star Trek literature, a relaunch is an unofficial name for a series that has ended and then been restarted, either in a different media or creative direction. The relaunch will usually extrapolate from the finish of the previous direction and establish new events going forward from that point, as an ongoing story arc.
For example, the first noted relaunches in Star Trek novel series were when the canon Deep Space Nine and Voyager television runs came to an end. After novelizing the finales of the series, the Pocket Books series for both parts of the franchise turned to a new direction, abandoning older numbering systems, and most importantly, being sequential or serial in nature, with stories over multi-book arcs. When The Next Generation novels turned to a serial format, the series was considered to be relaunched, even though the television version had ceased production years earlier, because the movie series had recently had an ending the novels could go forward from.
The term "relaunch" has never appeared on cover texts or matter regarding the publications of these series. The term is simply used to differentiate the change to an unnumbered, serialized format after a series finale gives the series a creative direction. There are no examples available of any official Pocket Books publicity referring to these series as "relaunches".
With these latest ongoing series, many multi-series crossovers have unified the direction of the books with themed developments that affect the direction of each series, meaning that many of the series are now synchronized chronologically based on the release order, with some flashbacks answering incomplete premises. The Enterprise relaunch is considered to be books that take place after the television finale, but they often have links to the overall continuity of the other crossovers, even though they are in a vastly different time period.
Prior to the relaunches, the numbered novels were often stand-alone stories that took place during a previous era of canon production, meaning the authors did not have license to make drastic alterations to the standard series format and continuity. For the relaunch series, stand-alone stories often are published as collections of short stories and novellas rather than being released as individual books. In the previous numbered novels, it was rare for collections or omnibus editions to be released.