Cross The Gap is a terminology used when describing a bridging device taking a ship, object, or person from one spatial coordinate to the other by folding the fabric of space and time so that the location and destination exist simultaneously in the same spatial reference. "The Gap," as it were, is, "crossed," by the said object, ship, or person by simply moving.
Tachyon Jump Gates are the only bridging devices known and used regularly by space faring vessels to travel from one point of space to the other by linked Tachyon Gates. Warp, despite its wording, is only fast enough to take a vessel from a planet to another planet within the same system, it is not a bridging device and, therefore, cannot cross the gap. However, some space travelers that cannot afford passage through Tachyon Gates have resorted to using warp to travel from one system to the next however extending travel times.