The NASDAQ (National Association of Securities Dealers Automated Quotations) is an electronic marketplace for trading stocks, and is also used to track major Technology stocks.
The NASDAQ Composite is an index of over 3,000 publicly traded companies on the NASDAQ stock market, which includes the world's biggest and most relevant technology companies - Apple, Google, Amazon, Intel, Oracle, and so on.
What does it Mean to be "Listed"?
What is After-Hours Trading?