Element, n. The basic building blocks of which all matter is built.
According to the ancient Greeks, there were four elements: Earth, Air,
Fire, and Water. Science has progressed beyond that; matter generally
consists of atoms, the ultimate, indivisible unit. Atoms in turn are
built of more fundamental and elementary particles, and the elementary
particles combine in various ways to generate the forms of matter we
know of -- Solid, Liquid, Gas, and Plasma.
- -- Hayward's Unabridged Dictionary