A Router is a network device. A network is an interconnection of devices for transferring information.

Data is transferred as packets which are sent to destinations. The destinations are identified by an address called as an IP address.

Networks follow certain protocol as some rules are needed for proper data transfer. The ISO/OSI model and the TCP/IP model define the rules/layers for networking.

Routers take care of the Network layer in these models. Thus Router is the device which helps in transferring packets to specific destinations.