Tonás ([toˈnas]) is the name given to a palo or type of flamenco songs. It belongs to the wider category of Cantes a palo seco, that is, palos which are sung without accompaniment or a cappella. Owing to this feature, they are considered by traditional flamencology to be the oldest surviving musical form of flamenco. The first flamenco singer known in history, Tío Luis el de la Juliana, who lived in Jerez de la Frontera in the last third of the 18th century was said to have excelled in this palo.
Other cantes a palo seco, such as martinetes and debla are sometimes classified under tonás, while at other times they are referred to as palos on their own.
The tonás were almost in disuse by the end of the 19th century. The reason seems to be that they were considered a difficult style by the general public, and therefore were not considered apt for the stage. Although there were always some singers that kept singing them in private gatherings, their practical banning form the stage resulted in the total oblivion of some toná styles.
During the 1950s, with the reappraisal of purism led by singers like Antonio Mairena, the tonás came back into use, and came to be considered as the main flamenco style together with seguiriya and soleá.