"The Dow Jones Industrial Average (DJIA) is a price-weighted average of 30 significant stocks traded on the New York Stock Exchange (NYSE) and the Nasdaq. The DJIA was invented by Charles Dow in 1896.
Often referred to as "the Dow," the DJIA is one of the oldest, single most-watched indices in the world and includes companies such as the General Electric Company, the Walt Disney Company, Exxon Mobil Corporation and Microsoft Corporation. When the TV networks say "the market is up today," they are generally referring to the Dow." - Investopedia