An electronic system created by the NASD to facilitate trading by providing broker/dealers with bid/ask price quotes on stocks. The Nasdaq has no physical trading floor unlike the other stock exchanges. All trading rather is performed over a network of computers and telephones. The Nasdaq began when brokers started trading via telephone, and the network was later formalized computer in the early 1970s. Orders for stock are sent out electronically, where market makers list their buy and sell prices.