"travel." However, we have already discussed time travel here and here. We will say a little more about space travel and teleportation before turning to inter-universal travel.
Although the quantum jump FTL space travel in Poul Anderson's Technic History is called "hyperspace," this phrase usually means disappearing from ordinary space into some other kind of space, as in Anderson's Planet Of No Return.
Although the term "teleportation" is not used, spaceships in World Without Stars can make an instantaneous jump even to another galaxy but must first match the relative velocity of the target galaxy. In The Enemy Stars, fuel and crews are teleported to slower than light interstellar spaceships and people teleport between Earth and the extrasolar colonies.
In Operation Chaos (New York, 1995):
"'The salamander uses a simple diffraction process to change the spatial coordinates of psi squared, in effect going from point to point without crossing the intervening distance, much like an electron making a quantum jump...'" (p. 83)
A succubus attacked by a werewolf:
"'...struggled to change the mathematical form of its Schrodinger function, thus fleeing to the Low Continuum where it belonged and leaving [the werewolf] with the exchange mass." (p. 118)
We now encounter a rule to the effect that, when traveling from universe A to universe B, a body must change places with a corresponding mass in universe B, thus displacing that mass to universe A, and must reverse the exchange for the return journey, even though such a rule is not mentioned in other texts about inter-universal travel.