Definition of: equation

(i·kwā′zhən, -shən) noun
1. The process or act of making equal; equal division; equality.
2. Math. A statement expressing (usually by the symbol =) the equality of two quantities.
3. Chem. A symbolic representation of a chemical reaction, as Na₂CO₃ + H₂SO₄ = Na₂SO₄+CO₂+H₂O. The first member includes the substances reacting; the second, the products. The sum of the quantities of the two members must be equal.
—e·qua′·tion·al adjective
—e·qua′tion·al·ly adverb