ISP – Internet Service Provider is a company that provides connectivity to the Internet and other related services. An ISP has the infrastructure required to have a point of presence (POP) to provide the customers a local connection to the Internet.
In order to connect to the ISP the customer need a device like ADSL modem, Router, Cable modem etc.

ISPs for example: AOL, AT&T, Comcast, Earthlink, Verizon.