What does the term "volta" refer to in music?

The term "volta" in music specifically refers to a type of form or structure within a piece, often indicating a return to a section of music. It is commonly used to denote a repeated section and can also indicate different variations of a repeated theme. This context aligns with the notion that "volta" relates to the organization of musical time, particularly in terms of revisiting sections within a composition.

In contrast, the other terms present different concepts in music: "measure" refers to the unit of time in music defined by a specific number of beats, "key" indicates the tonal center or scale that a piece of music is based around, and "tempo" pertains to the speed at which a piece of music is played. Each of these terms relates to aspects of musical structure or execution rather than the concept encapsulated by "volta."