RIP, Toots Hibbert, originator of the term "reggae." The Maytals' 1968 song "Do the Reggay" is credited in the @OED with the first known use, originally referring to a kind of dance. Toots, when asked later, said it came from a Jamaican word "streggae" meaning "raggedy." 1/

Did Toots Hibbert originally spell the word "reggae" or "reggay"? We don't know for sure. The original release of the "Do the Reggay/Reggae" single in Jamaica on the Beverley's label didn't print the title. Someone wrote "Reggae, Maytals" on this label. 2/ https://www.discogs.com/The-Maytals-Beverleys-All-Stars-Do-The-Reggay-Motoring/release/7515329

When the single was released in the UK on the Pyramid label later in 1968, it appeared as "Do the Reggay." But perhaps that was just an approximation of the new word "reggae" that Toots & The Maytals were introducing. 3/ https://www.discogs.com/The-Maytals-Beverleys-All-Stars-Do-The-Reggay-Motoring/release/3467392

In any case, the word "reggae"/"reggay" originally referred to "a dance characterized by bent knees and swaying improvised movements of the upper body, originally performed to the shuffling, syncopated rhythm typical of the earliest reggae music," as the @OED puts it. 4/

Here's the earliest known example of "reggae" in print from the Daily Gleaner of Kingston, Jamaica, from Sep. 7, 1968. It's an advertisement for The Rainbow Club, where the clientele was invited to "come do this brand new dance, THE REGGAE." 5/ https://newspaperarchive.com/entertainment-clipping-sep-07-1968-1963169/

As so often happens, the name of a new dance became the name for the music accompanying the dance. By late 1968, "reggae" could mean a style of music "characterized by a strongly accentuated offbeat and usu. a prominent bass line & a simple harmonic structure" as per the @OED. 6/

Here's an article from the Daily Gleaner from Nov. 22, 1968 indicating that "reggae" was already shifting to label the music. "If there were any composers of 'The Reggae' present then he would be sure that 'Carmen' would soon be put to the Reggae beat." 7/ https://newspaperarchive.com/entertainment-clipping-nov-22-1968-1963232/

I found these early citations for "reggae" in 2005 when looking through the Daily Gleaner in a news archive, and shared them on the @americandialect mailing list. They were later added to the @OED's "reggae" entry, which now gives the full history. 8/end http://listserv.linguistlist.org/pipermail/ads-l/2005-January/045320.html