What term is used for a network device that combines the function of a modem and a router?

A network device that combines the functions of a modem and a router is referred to as a gateway. This term specifically denotes a device that serves as a "gate" between two networks, particularly between a local network and the Internet. It performs the essential tasks of translating communications between these networks, ensuring data packets are correctly directed and formatted for both sides.

In the context of networking, modems and routers typically serve different purposes. A modem connects to the internet service provider and modulates and demodulates signals for data transmission, while a router connects various devices within a local network, directing traffic and managing network communication. A gateway seamlessly integrates these two functions, thus simplifying configurations and reducing the number of devices required.

Other options like a bridge, access point, and dual-function device do not accurately describe a device that fully integrates the roles of both a modem and a router in the same context as a gateway does. A bridge mainly connects two separate networks at the data link layer, while an access point serves as a hub that allows wireless devices to connect to a wired network. Dual-function device is a descriptive term but is not the standard terminology used to refer to this combination in networking.