A scherzo is a very fast section of classical music, often within a larger composition. A scherzo is usually upbeat and sometimes even humorous.
The plural form of scherzo is scherzi. Many symphonies and sonatas include scherzi, often in their second or third movements. The scherzo developed from the minuet, another lively musical form which itself came from a French dance. In Italian, scherzo means "joke" or "sport," from the root word scherzare, "to jest or joke," and this describes the lighthearted mood of many scherzi.