Word of Recall is a 6th level Cleric spell that states
You (...) teleport to a previously designated sanctuary.
It defines this sanctuary as
(...) a location, such as a temple, dedicated to or strongly linked to your deity.
The text of the spell says nothing about interplanar travel, however we have other spells to look at for reference:
- Teleportation Circle is a 5th level spell that opens a short-lived portal to a predetermined prepared location on the same plane of existence;
- Teleport is a 7th level spell that doesn't allow planar travel, and can be inaccurate depending on the caster's familiarity with the target location;
- Plane Shift, also a 7th level spell, is designed for planar travel, but seems somewhat inaccurate, depending on DM fiat;
Teleportation Circle shares the most similarities with Word of Recall, requiring prior setup and a designated location prepared in advance. However both the Circle and Teleport require the target location to be on the same plane of existence, and Plane Shift can be inaccurate. I guess the single class limit of Word of Recall and the setup needed might balance the possibility of planar travel, but I'd rather not guess the design principles of the official rulemakers. Thus, the question: