Also, in many systems, the elements have been Earth, Air, Fire, and Water. These are carried through to today in the western astrology, as each zodiac sign has an element it is associated with. The four humours were also each related to an element. These elements are also used in theory of chinese medicine.
I believe it was the Greeks that also added Ether as an element, at about the same time that other Greeks were positing a monist(?), particulate world-composition (you know, atoms!).