The energetic measure of aromaticity usually referred to as resonance energy (RE) is shown to possess a remarkable stoichiometric interpretation. Namely, the RE may be uniquely partitioned into a linear sum of contributions associated with group additivity (GA) response reactions (RERs). This new result is a powerful tool for critical analyses of various energetic approaches to RE. In particular, the single reaction scheme approach that is routinely used to evaluate RE is shown to be a particular case of the general GA method.