noun
stock index; stock market index; stock price index
A financial term referring to a statistical measure of changes in a portfolio of stocks representing a portion of the overall market. Common examples include the Nikkei 225 and TOPIX.
The Nikkei Stock Average is calculated based on the stock prices of 225 companies listed on the Tokyo Stock Exchange.
株価指数が大幅に下落したため、投資家の間に不安が広がった。
As the stock index fell sharply, anxiety spread among investors.