A cadenza is usually now taken to mean a portion near the end of a movement of a concerto in which the orchestra stops playing, leaving the soloist to play alone in free time (without a strict, regular pulse). At the end of the cadenza, the orchestra re-enters, and generally finishes off the movement on their own.

The cadenza was originally a vocal flourish improvised by a performer to elaborate a cadence in an aria. It was later used in instrumental music, and soon became a standard part of the concerto. Originally, it was improvised in this context as well, but during the 19th century, composers began to write cadenzas out in full. Third parties also wrote cadenzas for works in which it was intended by the composer to be improvised, so the soloist could have a well formed solo that they could practice in advance. Some of these have become so widely played as to virtually be a part of the original piece, as is the case with Joseph Joachim's cadenza for Johannes Brahms' Violin Concerto.

Nowadays, very few performers improvise their cadenzas, and very few composers have written concertos within the last hundred years that include the possibility of an improvised cadenza.

A famous example of a cadenza is Rachmaninov's Third Piano Concerto, in which the first movement features a long and difficult cadenza. Rachmaninov even wrote two or three alternative cadenzas for this movement the pianist can choose from.

Cadenzas are also found in instrumental solos with piano or other accompaniment, where they are placed near the beginning or near the end or sometimes in both places. (e.g. "The Maid of the Mist," cornet solo by Herbert L. Clarke.)

A cadenza is also a military tradition of marking the pass when in march, in the order: left, left, left-right-left. This habit is forbidden in many countries.