Allegro (Italian: cheerful, lively) is generally taken as fast, although not as fast as vivace or presto. Allegretto is a diminutive, meaning slightly slower than allegro. These indications of speed or tempo are used as general titles for pieces of music headed by instructions of this kind. The first movement of a classical sonata, for example, is often 'an Allegro', just as the slow movement is often 'an Adagio'.