for sure , those links are super complicated to digest all at once..i've found an easier definition for myself here:

Atom economy (atom efficiency) describes the conversion efficiency of a chemical process in terms of all atoms involved. In an ideal chemical process the amount of starting materials or reactants equals the amount of all products generated (see stoichiometry) and no atom is wasted. Recent developments like high raw material (such aspetrochemicals) costs and increased sensitivity to environmental concerns have made atom economical approaches more popular. Atom economy is an important concept of green chemistry philosophy

Atom economy can be written as:

% atom economy = 

Atom economy is just one way to evaluate a chemical process. Other criteria can include energy consumption, pollutants released and price.