It's the "spell" that opens the map in Final Fantasy 1. You can access it at any time you want by pressing B and select at the same time, even before speaking to the witch Matoya's broomsticks who tell it to you (they don't tell you what it does). I would've known it but in most versions of the game it's "Tceles nottub B."
I think the phrase is also in FF2, spoken by an insignificant NPC in an insignificant town at only an early part of the game. The map is opened the same way as in FF1 but requires a ring you get by speaking to a significant NPC in a significant town during your first mission of the game. If I remember right, there's a little kid in a side town between Altair and Fynn who comments on the ring and says its original owner opened the map by speaking the "incantation"
