Frevo denotes both a musical genre and a dance style from Pernambuco State that evolved together between the end of of the 19th century and 1915, as a syntesis between several popular styles of that period -such as Modinha, Quadrilha, Polca, Pastoril, Maxixe etc.- and military march band music (most notably the Dobrado), similar to the Marchinha Carioca from Rio de Janeiro, albeit with a stronger emphasis on rythm and 'agressive' military aspects. The term ffevo derives from the verb ferver (=to boil), and was first used around 1908.
Frevo compositions are 2/4, up tempo, normally divided bewteen two parts of 16 bars, intersected by a bridge ('passagem'). Since the 1930, three classic types of Frevo were distinguished: Frevo de Rua (=street frevo) the original brass band form and always instrumental (again subdivided into Abafo, Ventania, Coqueiro and Marcha-Regresso), Frevo do Bloco (=block or group-frevo) rooted in the Pastoril and played by string instruments, and Frevo Canção (=frevo-song) a tamed dance hall adaptation, a parallel to the relation between Samba-Canção and Samba.
Osmars and Dodô's 'electrification' the Frevo da Rua played by the Vasssourinhas orchestra would add another member to this family, named by a variaty of terms, such as Frevo da Bahia (by Osmar and Dodô), Frevo Novo (by Caetano Veloso) or Frevo do Trio.