The branch of economics that studies the aggregate, or total, behavior of all house holds and firms. For further details see: THE FINANCIAL SYSTEM AND THE ECONOMY: Principles of Money and Banking.
Monetary Policy: there are three basic monetary policy tools or instruments available to the central bank in its conduct of monetary policy. These are required reserve ratio, discount rate, and open-market operations.
Trade Policies, broadly defined, are policies designed to directly influence the amount of goods and services exported or imported. For further details see: Macroeconomics by N. Gregory Mankiw.
Fiscal Policy is government spending and taxing decisions to speed up or slowdown the level of economic activity. For further details see: THE FINANCIAL SYSTEM AND THE ECONOMY: Principles of Money and Banking.