BLUEGRASS
bluegrass
(noun) a type of country music played at a rapid tempo on banjos and guitars
Bluegrass, Bluegrass Country, Bluegrass Region
(noun) an area in central Kentucky noted for its bluegrass and thoroughbred horses
bluegrass, blue grass
(noun) any of various grasses of the genus Poa
Source: WordNet® 3.1
Etymology 1
Noun
bluegrass (countable and uncountable, plural bluegrasses)
Kentucky bluegrass, Poa pratensis.
Etymology 2
Noun
bluegrass (uncountable)
(uncountable) A style of country music with roots in Scots-Irish Appalachian folk music, blues, and jazz and characterized by banjos, fiddles, acoustic guitars, dobros, and mandolins; but containing no drums, electric guitars, pianos or other keyboard or wind instruments.
Source: Wiktionary