is a router the same thing as a modem
Modem - Box from your ISP that connects to the internet. It actually connects to the phone line or the coaxial cable or whatever physical line you have. It normally has at least an ethernet connection, sometimes a USB as well. Router - Box that connects to the modem and allows multiple devices to use that internet connection at the same time. It also lets the devices talk to each other (so you can transfer files in your house or whatever).