Allegro is a musical term that indicates a fast and lively tempo. It is often used in classical music to describe a section of a piece that should be played quickly, creating an energetic and joyful atmosphere. The term originates from the Italian word for "cheerful" or "merry." In the context of music notation, allegro typically suggests a tempo of around 120 to 168 beats per minute. Composers use this term to guide musicians on how to interpret the speed of a piece, ensuring that the performance conveys the intended emotion and character.