A few defined terms are in order.
Normal time: 1 subjective second per objective second. This means that you and any other object that remains at a fixed distance from you, and that experiences the same gravity gradient as you, are travelling into the future at the same rate: 1 second per second.
Time travel: 1 subjective second per more-than-one objective second. This means that for every second that the traveler experiences, more than 1 second elapses for an observer. This may be due to the traveler's relativistic velocity in relation to the observer, the traveler being in suspended animation, or the traveler being in a more intense gravity field than the observer. Traveling into the past is expressed as 1 subjective second occurring in -1 objective seconds.
(I wonder what happens to the "Time Traveler" who experiences 1 second of subjective time for every microsecond of objective time... maybe the objective observer watches as the traveler grows old, dies, and decays in a matter of minutes? "I told him to calibrate that auxiliary framing correlator! Now he's gone and made an ash of himself...")
Teleportation: Any change in location that takes zero time to complete, both subjectively and objectively. The velocity is "undefined" since dividing the distance traveled by zero time yields an undefined value (some call this value "infinity" as a convenient handwave). Some gaming systems have declared that some small amount of time (femtoseconds?) elapses during the time it takes to teleport from "here" to "there" or back.
Faster Than Light travel: Any change in location at a velocity greater than 299,792.458 kilometers per second, and that is not instantaneous.
Slower than light travel: Any change in location that occurs at a velocity less than 299,792.458 km/s.
***
Commentary, with Star Trek references:
For some, the "Light Barrier" (c = 299,792.458 km/s)is a velocity that can never be achieved, only transited. Gene Roddenberry called this value "Warp One". The earliest warp engines required the vessel to accelerate to as close as possible to "c" in order to breach the "Warp Threshold", much as current ramjets have to be accelerated to a certain minimum velocity before they can operate. Newer warp engines allow a starship to achieve warp from almost a standing start.
"Traveller" Jump Drives must be more efficient than "Star Trek" Warp Engines, in that there is no need for the vessel to accelerate to some minimum velocity before an FTL jump can occur.
-KR-
