Microeconomics relates to the study of economics at a micro, or personal scale. Accordingly, it looks at how households and firms make decisions to allocate limited resources.

Opportunity cost is the cost of doing something. For example, if I married Selena, the opportunity cost of that would be to marry Miley, or another girl.

The supply and demand curve is a graph of price versus quantity, with the demand curve a negative slope, and the supply curve a positive slope.

Macroeconomics relates to the study of economics on the macro, or global scale.

Macroeconomics looks at economy-wide issues, such as growth, inflation and unemployment