section_path: History/Classical definitions
section_name: Classical definitions
paragraph_text: Classical definitions
  
  Ancient philosophy posited a set of classical elements to explain observed patterns in nature. These elements originally referred to earth, water, air and fire rather than the chemical elements of modern science.
  
  The term 'elements' (stoicheia) was first used by Greek philosopher Plato around 360 BCE in his dialogue Timaeus, which includes a discussion of the composition of inorganic and organic bodies and is a speculative treatise on chemistry. Plato believed the elements introduced a century earlier by Empedocles were composed of small polyhedral forms: tetrahedron (fire), octahedron (air), icosahedron (water), and cube (earth).
  
  Aristotle, c. 350 BCE, also used the term stoicheia and added a fifth element, aether, which formed the heavens. Aristotle defined an element as:
  
  Element – one of those bodies into which other bodies can decompose, and that itself is not capable of being divided into other.