The SAGE Glossary of the Social and Behavioral Sciences defines economics as,
The study of how individuals, house holds, and societies choose to use their scarce resources efficiently in order to satisfy their diverse wants. By definition, economics is a social or behavioral science because it studies human behavior just like other social sciences, but it emphasizes the need to make wise choices in order to use scarce resources in an efficient way to satisfy diverse wants.
Resources are the factors of production, the inputs, and managerial skills that are required to produce goods and services. These are land, labor, capital, and entrepreneurial skill. The factors of production are scarce because of the limitless wants of economic agents and the competing uses to which the resources can be committed. Scarcity is therefore a relative concept, meaning that economic resources are scarce relative to limitless wants and the competing demands for available resources…
The two broad categories of economics are microeconomics and macroeconomics. Microeconomics is the study of individuals, households, and firms, while macroeconomics studies the aggregate economy and aggregate variables, such as national income, national saving, the general price level, and the national employment rate. (Credo)