Source : Webster's Revised Unabridged Dictionary (1913)

Scherzo \Scher"zo\, n. [It.] (Mus.)
   A playful, humorous movement, commonly in 3-4 measure, which
   often takes the place of the old minuet and trio in a sonata
   or a symphony.

Source : WordNet®

scherzo
     n : a fast movement (usually in triple time)
     [also: {scherzi} (pl)]