The federal funds rate is the interest banks charge each other for overnight loans. Set by the Federal Reserve, it's a basis for other interest rates.

Sales of previously owned homes in the United States fell sharply in August, despite mortgage rates plummeting that month. But much more housing demand will likely be unleashed onto the market after the Federal Reserve finally cut interest rates this week for the first time in four years — and signaled more rate cuts by year’s end.

If the Fed cuts interest rates today, borrowers will likely see interest rates ease off their peaks on things like credit cards and auto loans.