passacaglia
noun
pas·sa·ca·glia ˌpä-sə-ˈkäl-yə 
ˌpa-sə-ˈkal-yə
ˌpa-sə-ˈkal-yə 1
a
: an old Italian or Spanish dance tune
b
: an instrumental musical composition consisting of variations usually on a ground bass in moderately slow triple time
2
: an old dance performed to a passacaglia
Example Sentences
Recent Examples on the Web The grandeur of the passacaglia, the urgency of the toccata and the majesty of the chorale reminded listeners of this work’s value. 
Howard Reich, chicagotribune.com, 10 Oct. 2019 The ciaccona — or passacaglia, a term often used interchangeably — typically features variations over a repeating bass, and Bollinger chose her examples well. Jeremy Eichler, BostonGlobe.com, 4 May 2018 The Impromptu is structured like a Baroque passacaglia, with an insistent chorale-like theme put through myriad tinkling, brash and eerie variations. Anthony Tommasini, New York Times, 9 Feb. 2018
Howard Reich, chicagotribune.com, 10 Oct. 2019 The ciaccona — or passacaglia, a term often used interchangeably — typically features variations over a repeating bass, and Bollinger chose her examples well. Jeremy Eichler, BostonGlobe.com, 4 May 2018 The Impromptu is structured like a Baroque passacaglia, with an insistent chorale-like theme put through myriad tinkling, brash and eerie variations. Anthony Tommasini, New York Times, 9 Feb. 2018 Word History
Etymology
modification of Spanish pasacalle, from pasar to pass + calle street, from Latin callis path — more at pase
First Known Use
1659, in the meaning defined at sense 1a