From japanese kanji 二 (ni) meaning "two", 階 (kai) meaning "floor, storey" combined with 堂 (dō) meaning "temple". The last name is a name of a clan of Japanese samurai that ruled the Iwase District of Mutsu Province during the Sengoku period during the Kamakura era. The founder was Nikaido Yukimasa and they lived in the Sukagawa Castle. Other kanji combinations are possible. A fictional character is named Saki Nikaido from Zombieland Saga.