reservoir: tank used for collecting and storing a liquid (as water or oil)
container: any object that can be used to hold things (especially a large metal boxlike object of standardized dimensions that can be loaded from one form of transport to another)
manichaeism: a religion founded by Manes in the third century; a synthesis of Zoroastrian dualism between light and dark and Babylonian folklore and Buddhist ethics and superficial elements of Christianity; spread widely in the Roman Empire but had largely died out by 1000