The Dow Jones Averages, also known as the Dow Jones Industrial Average or DJIA, is a well-known stock market index that tracks 30 of the largest and most influential public companies in the United States. However, there are several synonyms that are often used interchangeably with DJIA, including simply "the Dow", the Dow Jones Index, the Dow 30, and the Industrial Average. While these terms all refer to the same stock market index, they are all useful in different contexts. For example, "the Dow" is often used informally in everyday conversation, while the "Dow Jones Index" is used more formally in financial reporting.