What is microeconomics?

Microeconomics is like the smaller scale of Economics. Microeconomics deals with the decisions of individual households. It takes into consideration the factors that affect the decisions of these individuals and how this affects the market and the economy.

Macroeconomics on the other hand looks at the bigger picture. It looks at all the firms and all the consumers in the market and considers all the market activity happening inside a larger geographical scale.

*Needs more elaboration, my answer is quite simplistic.