A fascinating site - one of the favourite places I've been to.
The Maya name "Chich'en Itza" means "At the mouth of the well of the Itza." This derives from chi', meaning "mouth" or "edge", and ch'e'en, meaning "well." Itzá is the name of an ethnic-lineage group that gained political and economic dominance of the northern peninsula. The name is believed to derive from the Maya itz, meaning "magic," and (h)á, meaning "water."