Samba (Portuguese pronunciation: [ˈsɐ̃bɐ] ) is a name or prefix used for several rhythmic variants, such as samba urbano carioca (urban Carioca samba), samba de roda (sometimes also called rural samba), amongst many other forms of samba, mostly originated in the Rio de Janeiro and Bahia states.

Samba is a broad term for many of the rhythms that compose the better known Brazilian music genres that originated in the Afro-Brazilian communities of Bahia in the late 19th century and early 20th century, having continued its development on the communities of Rio de Janeiro in the early 20th century.

Having its roots in the Afro-Brazilian Candomblé, as well as other Afro-Brazilian and Indigenous folk traditions, such as the traditional Samba de Caboclo, it is considered one of the most important cultural phenomena in Brazil and one of the country's symbols.

Present in the Portuguese language at least since the 19th century, the word "samba" was originally used to designate a "popular dance". Over time, its meaning has been extended to a "batuque-like circle dance", a dance style, and also to a "music genre". This process of establishing itself as a musical genre began in the 1910s and it had its inaugural landmark in the song "Pelo Telefone", launched in 1917. Despite being identified by its creators, the public, and the Brazilian music industry as "samba", this pioneering style was much more connected from the rhythmic and instrumental point of view to maxixe than to samba itself.

Samba was modernly structured as a musical genre only in the late 1920s from the neighborhood of Estácio and soon extended to Oswaldo Cruz and other parts of Rio through its commuter rail. Today synonymous with the rhythm of samba, this new samba brought innovations in rhythm, melody and also in thematic aspects. Its rhythmic change based on a new percussive instrumental pattern resulted in a more "batucado" and syncopated style – as opposed to the inaugural "samba-maxixe" – notably characterized by a faster tempo, longer notes and a characterized cadence far beyond the simple ones palms used so far. Also the "Estácio paradigm" innovated in the formatting of samba as a song, with its musical organization in first and second parts in both melody and lyrics. In this way, the sambistas of Estácio created, structured and redefined the urban Carioca samba as a genre in a modern and finished way. In this process of establishment as an urban and modern musical expression, the Carioca samba had the decisive role of samba schools, responsible for defining and legitimizing definitively the aesthetic bases of rhythm, and radio broadcasting, which greatly contributed to the diffusion and popularization of the genre and its song singers. Thus, samba has achieved major projection throughout Brazil and has become one of the main symbols of Brazilian national identity. Once criminalized and rejected for its Afro-Brazilian origins, and definitely working-class music in its mythic origins, the genre has also received support from members of the upper classes and the country's cultural elite.

At the same time that it established itself as the genesis of samba, the "Estácio paradigm" paved the way for its fragmentation into new sub-genres and styles of composition and interpretation throughout the 20th century. Mainly from the so-called "golden age" of Brazilian music, samba received abundant categorizations, some of which denote solid and well-accepted derivative strands – such as bossa nova, pagode, partido alto, samba de breque, samba-canção, samba de enredo and samba de terreiro – while other nomenclatures were somewhat more imprecise – such as samba do barulho (literally "noise samba"), samba epistolar ("epistolary samba") ou samba fonético ("phonetic samba") – and some merely derogatory – such as sambalada, sambolero or sambão joia.

The modern samba that emerged at the beginning of the 20th century is predominantly in a 24 time signature varied with the conscious use of a sung chorus to a batucada rhythm, with various stanzas of declaratory verses. Its traditional instrumentation is composed of percussion instruments such as the pandeiro, cuíca, tamborim, ganzá and surdo accompaniment – whose inspiration is choro – such as classical guitar and cavaquinho.

In 2005 UNESCO declared Samba de Roda part of Intangible Cultural Heritage of Humanity, and in 2007, the Brazilian National Institute of Historic and Artistic Heritage declared Carioca samba and three of its matrixes – samba de terreiro, partido-alto and samba de enredo – as cultural heritage in Brazil. Also, in 2018, the prefecture of Salvador proclaimed Samba Junino, also known as Samba Duro, an urban variation of Samba to be part of its Cultural Heritage.