Scherzo
A Scherzo is a piece of music which is quite fast. In the 19th century Romantic composers started to write scherzos in their symphonies and sonatas instead of the traditional minuets. They are similar to a minuet, always with three beats in a bar,  but they are faster and less "polite". Some composers like Chopin and Brahms wrote scherzos as separate pieces for the piano.