circular-flow diagram
a visual model of the economy that shows how dollars flow through markets among households and firms

production possibilities frontier
a graph that shows the combinations of output that the economy can possible produce given the available factors of production and the available production technology

microeconomics
the study of how households and firms make decisions an dhow they interact in markets
macroeconomics
the study of economy-wide phenomena including inflation, unempolyment, and economic growth
positive statements
claims that attempt to describe the world as it is
normative statements
claims that attempt to prescribe how the world should be