A gateway is a point of entry that connects two different networks or systems, allowing data to flow between them. It acts as a translator, enabling communication between devices that use different protocols or formats. For example, a router can serve as a gateway between a home network and the internet, directing traffic and ensuring that data reaches its intended destination. In the context of computer networks, gateways can also refer to software applications that facilitate access to services or resources. For instance, a payment gateway allows online transactions by securely processing credit card information and connecting to banks, ensuring safe and efficient payment processing.