Gnomon

A Gnomon is the center of the Sundial. Teridax had one under the Coliseum, seen in BIONICLE 2: Legends of Metru Nui. There was also a Sundial on Mata Nui, in Onu-Wahi. Nixie found the Gnomon of this sundial in the foothills if Mt. Ihu, and later gave it to Takua, who returned it.