cadenza
A fancy solo part near the end of a music piece.
A cadenza is a section near the end of a piece of music where a soloist gets to show off their skill with an elaborate, often improvised solo while the orchestra pauses and waits. It's like the musical equivalent of a figure skater's final spectacular spin sequence: everyone else stops to watch one performer display their full talent.
Cadenzas appear most often in concertos, which are pieces written for a solo instrument with orchestra accompaniment. When the cadenza arrives, the conductor may lower the baton, the violinists rest their bows, and the soloist takes center stage. A pianist might race through dazzling runs up and down the keyboard. A violinist might play impossibly fast passages or jump between high and low notes. The soloist usually plays without following a strict tempo, speeding up and slowing down for dramatic effect.
Originally, performers improvised cadenzas on the spot, creating new music in the moment based on themes from the piece. This demonstrated both technical skill and creative understanding of the music. Today, most performers play written-out cadenzas, either composed by the original composer or by famous performers, though some still improvise.