Why is macroeconomics the study of a big lump?

There are many branches of economics. One amongst them is macroeconomics. It studies the individual variables in their aggregate form. Some of the variables concerning macroeconomics are a gross domestic product (GDP), inflation rate, unemployment rate, the level of output in the economy, interest rates and so on. It studies big issues which concern the economy at the national level. Due to the fact that macroeconomics studies the economy as a whole, it is called the study of a big lump.