I posted this in TGGP's comments a few seconds ago:
I may have a shitty understanding of macroeconomics because to me “macro” means big, so I think it means economic study on the largest order of scale (global economics, or the largest salient subdivisions of global economics). So that studying the effect of policy on the economic wellbeing of the USA would be macroeconomics. In that sense, I see its hard to deny that Marx was a macroeconomic historian.
“Micro” means small, so I think of microeconomics as the study of economics on the smallest scale, and perhaps slightly larger scales that don’t approach the salient features of macroeconomics. So that an experiment of how 100 people behave in a market with certain starting conditions and regulations would be a microeconomic experiment.
Perhaps my understanding of macroeconomics and microeconomics is way off -but then I think that would be an indication that the nomenclature is shitty.