What is an amateur radio station that connects other amateur stations to the internet?

A gateway is specifically defined in amateur radio as a station that provides a bridge or connection between an amateur radio RF network and the internet. This is what allows systems like EchoLink, IRLP, or D-STAR to link repeaters across the globe using internet infrastructure. Other options serve different purposes. A repeater simply receives and retransmits an RF signal to extend local range, while a digipeater does the same specifically for digital packets. A beacon continuously transmits a one-way signal to help others test propagation. Since the question asks about connecting to the internet, 'gateway' is the correct answer.