Horn's death was announced by Verve, her record company since 1986 and the vehicle of a comeback that restored her to jazz stardom.
Horn's style was instantly recognizable: she performed ballads at a glacially slow pace, but—like trumpeter Miles Davis, a mentor—with a sharp delivery that seemed to contain a quivering energy in its silences.
"Shirley Horn was a true innovator," said Ron Goldstein, president and CEO of the Verve Music Group. "She created a unique style of playing and singing that was not only original, but so penetrating and so much her own that few dared try to copy it. "
Horn formed her first trio as a teenager, and recorded her first album, Embers and Ashes, in 1960. Davis heard the album and arranged for her to open for him at New York's Village Vanguard. After making three major-label albums in the mid 1960s, however, Horn largely retired in order to raise her family.
She continued to perform in the Washington, D.C., area, but did not reach a wide audience again until the late 1980s, when she made the first of a series of popular recordings for Verve. Her albums for the company received eight Grammy nominations, and her 1998 tribute to Davis, I Remember Miles, won a Grammy Award.
Last year, Horn was named a National Endowment for the Arts Jazz Master, and the Kennedy Center paid tribute to her in December.