central bank

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A national monetary authority, such as the US Federal Reserve, which regulates the money supply and credit, issues currency, and manages the rate of exchange.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The principal monetary authority of a country or monetary union; it normally regulates the supply of money, issues currency and controls interest rates. It usually oversees banking activity within its country's borders.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a government monetary authority that issues currency and regulates the supply of credit and holds the reserves of other banks and sells new issues of securities for the government