However, in the context of anime and manga, especially in the popular series "Bleach", Mugetsu (無月) takes on a more specific meaning:
* The ultimate power of the Zanpakuto, "Tensa Zangetsu": In "Bleach," Mugetsu is the final, most powerful form of Ichigo Kurosaki's Zanpakuto, Tensa Zangetsu. It's a state of absolute power, sacrificing Ichigo's ability to use any other Zanpakuto powers in exchange for immense strength.
So, while the literal translation is "moonless," in the context of "Bleach," Mugetsu is best understood as the peak of power for a specific Zanpakuto.