The meaning and definition of Index -
For investors, an index represents a hypothetical, unmanaged portfolio of securities, the performance of which is used as a benchmark in measuring performance of actual securities or of markets in general. Investors cannot directly invest in an index although they can invest in mutual funds or exchange-traded funds that seek to match the holdings of an index. Common examples of an index include the Dow Jones Industrial Average and the Standard & Poor's 500. An investor cannot invest directly in an index. See also: Index Funds.