Proto-warp
Proto-warp, also called proto-jump, was a form of faster-than-light space travel that exceeded the limits of traditional warp drive. 

Proto-warp was used as a propulsion enhancement system in the  vessels launched by Starfleet in the late 24th century. It utilized a protostar located in the proto-drive. A third nacelle was needed in addition to the two warp nacelles when the drive was engaged. It was considered a high-priority system and used a large amount of energy. ()

To achieve proto-warp, the Protostar first needed to travel at its maximum regular warp velocity at warp 9.97, then extend the third nacelle, reconfigure the two warp nacelles into lower positions, and finally engage the proto-drive. Four thousand light years could be traversed in a single proto-warp. ()

Warp