The Dow, or Dow Jones Industrial Average, is a Wall Street statistic that tracks the performance of 30 large publicly traded companies in the United States. It is used as a barometer for the stock market and is often seen as an indicator of the overall health of the economy. The Dow is calculated by taking the sum of the prices of the 30 stocks and dividing it by a divisor, which is adjusted to account for stock splits and other corporate actions.