What does the term 'Allegro' indicate about the tempo of a piece?

The term 'Allegro' is an Italian musical term that indicates a brisk and lively tempo. Typically, it suggests a speed of around 120 to 168 beats per minute. This term is commonly used in music to create an upbeat and energetic feel to a piece. Understanding tempo markings is crucial in music, as they guide the performer on how a piece should be interpreted. In contrast, other tempo indications such as 'largo' suggest a slow tempo, 'moderato' denotes a moderate speed, and 'adagio' indicates a very slow tempo. Therefore, 'Allegro' distinctly falls into the fast category, making it the correct choice.