Plain English Meaning
A free service that beams weather and flight information up to your aircraft from FAA ground stations, so you can see things like radar pictures, weather reports, and notices on a cockpit display.
Full Definition
A free, one-way data service transmitted from FAA ground stations over the 978 MHz UAT (Universal Access Transceiver) link, providing aircraft equipped with a compatible ADS-B In receiver with weather and aeronautical information. Products typically include regional and radar imagery, , TAFs, , and , , , , , and . FIS-B is -only, in nature, and for , not for .