Wiktionary
chemical equation
n. (context chemistry English) a symbolic representation of a chemical reaction; reactants are represented on the left, and products on the right
Wikipedia
Chemical equation
A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side. The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers. The first chemical equation was diagrammed by Jean Beguin in 1615.