The Greeks built their calendar from the twelve principal constellations as they took their turns in the sky overhead, but the calendar was represented graphically by a circle in which figures representing the constellations were entered. This representation was called zodiakos kyklos, or the circle of the figures. The phrase originated from zodian - a figurine, usually of an animal - and kyklos, a circle. The phrase became abbreviated to zodiakos, which was taken into Latin as zodiacus and then into English with the spelling change.
