Like the Bank of England, the U.S.Federal Reserve has all but exhausted one of its most powerful tools for stimulating the economy -- lowering the key interest rate that banks charge to lend to each other.

VOA: standard.2009.03.18

So the interest rate the policy tool in the United the policy interest rate or key rate in the United States is called the Federal Funds Rate.

所以，利率美国的政策工具,美国的政策利率或是主要利率,叫做联邦资金利率。

耶鲁公开课 - 金融市场课程节选