Stands for "Internet Service Provider." In order to connect to the Internet, you need an ISP. It is the company that you (or your parents) pay a monthly fee to in order to use the Internet. If you use a dial-up modem to connect to your ISP, a point-to-point protocol (PPP) connection is established with another modem on the ISP's end. That modem connects to one of the ISP's routers, which routes you to the Internet "backbone." From there, you can access information from anywhere around the world. DSL and cable modems work the same way, except after you connect the first time, you are always connected.