Is it possible that Toriyama gave the sword of the Kaioshins the name "Z Sword" using the same reasoning as he did, when giving DBZ its title?Possible Ending #4: The Saiyans
So that brings us to the “Z” portion of the story, which naturally brings up the whole reasoning behind the name “DragonBall Z” to begin with. In his joint interview with Katsuyoshi Nakatsuru in the anime guide Son Goku Densetsu, Toriyama explained that he personally felt the name of the series was fine the way it way, but the anime staff wanted something new for this new section of the story, and so “DragonBall Z” was born. Why? Well, as Toriyama explains, “Z is the last letter in the alphabet, right? So, at the time I already really wanted to end the series, and so I made the title ‘Z’ to say ‘Hey, this is the end!’”
Since Herms' doesn't have it as an indicator for the Buu Arc ending, it seems like it's just baseless speculation at its best, but that doesn't stop me from asking: has Toriyama ever given any reason for why he gave the Z Sword that specific name?