What is a router?

In simple terms its a device used to set up networks simulationously or wirelessly

a router if im correct inthinking you mean computer wise is like a junction box, you would plug in your cable connection into the router then you plug your computers into the computer so they all have connection to thie internet, this is a helpfull thing because you only need tohe router on and you can use any of the computers connected to it on the internet with out any other computers switched on. using other methods such as networking/ethernet cards to join 2 computers together would mean you would need the main pc thats connected to the internet to be on for the other one to be able to access the internet. i hope this helps.

Router is a device that forwards data packets along networks. You can get the full information at: webopedia.com

A router is a device used to split internet between two or more computers. This is in simple words. Not exactly split but kind of share internet. It connects with your modem first and through router your DSL cable goes to you CPU. and It doesnt let effect your internet speed.