An Electronic Communication Network (ECN) is a type of trading platform that automatically matches buy and sell orders for securities in the financial markets. It allows traders to execute orders without the need for a traditional market maker, providing greater transparency, speed, and potential price improvement. ECNs facilitate electronic trading in both stocks and foreign exchange, offering access to a wide range of liquidity providers, enabling after-hours trading and typically charging lower fees compared to conventional exchanges. By connecting various market participants, ECNs enhance market efficiency and competition.