The percussion section of a Rio de Janeiro samba school is called the bateria.
The bateria supplies the rhythmic engine for a samba-school parade. It may include surdos, caixas, repiniques, tamborims, agogôs, and other percussion instruments. Musicians play interlocking patterns that support the school’s samba-enredo and help keep the enormous procession moving together.
A bateria is led by a mestre de bateria, who directs the musicians and shapes changes in rhythm, pauses, and musical effects. The section can contain hundreds of players, making it one of the loudest and most visually powerful parts of a Carnival parade.
The term should not be confused with the samba-enredo, which is the school’s theme song, or with the passistas, who are dancers. The bateria is specifically the instrumental percussion group. Different schools develop distinctive rhythmic identities while sharing the broader traditions of samba-school performance.