No one's covered Bluegrass yet, so I'll step up...
From the Wiki page: "Exactly when the word bluegrass itself was adopted to label this form is not certain, but is believed to be in the early 1950s,[5] and was derived from the name of the seminal Blue Grass Boys band, formed in 1939 with Bill Monroe as its leader. Due to this lineage, Bill Monroe is frequently referred to as the "father of bluegrass",[6] although his style drew upon the country, gospel, and blues music with which he had grown up."
"As Ralph Stanley himself said about the origins of the genre and its name: "Oh, (Monroe) was the first. But it wasn't called bluegrass back then. It was just called old time mountain hillbilly music. When they started doing the bluegrass festivals in 1965, everybody got together and wanted to know what to call the show, y'know. It was decided that since Bill was the oldest man, and was from the Bluegrass state of Kentucky and he had the Blue Grass Boys, it would be called 'bluegrass.""
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Fairy tales do not tell children the dragons exist. Fairy tales tell children the dragons can be killed. -- G. K. Chesterton
Officially diagnosed autistic. September 2023, suspected since 2010.