Short answers, pulled from the story.
Simulcast is the broadcasting of the same programme or event across more than one medium, resolution, service, or network at exactly the same time. The word is a portmanteau of "simultaneous broadcast" and has been in documented use since at least 1925.
The term was coined in 1948 by a press agent at WCAU-TV in Philadelphia. NBC and CBS had begun airing some programs simultaneously for both their radio and television audiences, which gave rise to the need for a word describing the practice.
The first UK simulcast using both television and FM radio to deliver stereo sound was on the 14th of November 1972, when the BBC broadcast a live classical concert from the Royal Albert Hall on both BBC2 and Radio 3. The first UK pop and rock simulcast followed on the 27th of May 1974, with Van Morrison's London Rainbow Concert on BBC2 and Radio 2.
Before stereo sound transmission over television was technically possible, broadcasters transmitted the audio portion of TV programs over FM radio so viewers could connect a stereo FM tuner to receive the sound in stereo. PBS stations used this method frequently for live concerts, and it was also how MTV carried stereo audio through cable networks in the 1980s.
The first cable TV concert simulcast was Frank Zappa's Halloween show on the 31st of October 1981, broadcast live from New York City's Palladium on MTV with the audio-only portion simulcast over FM's Starfleet Radio network. It was engineered by Mark G. Pinske using the UMRK mobile recording truck.
In the mid to late 1990s, Nintendo broadcast digital game data to the Satellaview unit while its satellite radio partner St.GIGA simultaneously broadcast orchestral music and voice acting by radio. The Satellaview hardware combined the two streams into a single audiotrack, creating what Nintendo called integrated radio-games.