A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork (e.g. the Internet) until it reaches its destination node.
A router is connected to two or more data lines from different IP networks.When a data packet comes in on one of the lines, the router reads the network address information in the packet header to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey.
Features of router
Its a Networking device.
Works on Network Layer (Layer 3 devices).
Directs data in a network. Passes data between home computers, and between computers and the modem.
Data transfer in the form of Packet.
Can connect to multiple PCs or networking devices via Ethernet or WiFi.
It is not necessary for internet connection, but provides additional security and allows for multiple connections.
Provides security measures to protect network.
Routers can share information between computers, but cannot connect to the internet without a modem.
Routers examine data packets to determine their destination, and so can contain firewalls to screen out attacks on the network.
Sources: google,Wikipedia and miscellaneous.