The word palo, in Spanish, has several meanings, the main one being "stick", "pole", "rod", "tree" or "branch", but in this case it has the sense of "suit of cards" i.e. category or classification.
Each palo is identified by a variety of musical features such as its rhythmic pattern, its mode, its characteristic motifs, the type of stanza used for the lyrics, and its origin.
For example, to determine that a song belongs to the palo called Bulerías, only the rhythm is taken into consideration, no matter its mode or stanza.
[1] Some palos such as granaínas, malagueñas, and fandango libre, are rendered in free rhythm, whereas most others are metered, that is, in compás.
Some modern flamenco artists have also performed these styles with instrumental accompaniment, a practice that is spurned by purists.
When martinetes are sung as musical support for dance, they are normally accompanied by a siguiriya type percussion, often using a hammer and anvil to evoke their hypothetical origin as cantes de fragua (songs from the smiths).
The bulerías is a special case in this group, as it is not constrained to the typical 12-beat scheme of soleá, but can also incorporate 6-beat and 3-beat sections.
The fandangos were immensely popular folkloric dances in large areas of Spain and Ibero-America during the 18th century.
It comprises tangos, tientos, farruca, garrotín and rumba and tanguillos, plus other rare palos such as marianas.
The farruca and the garrotín were folkloric songs originated probably in Asturias and Catalonia and brought to Andalusia, where they acquired flamenco characteristics.
These palos are supposed to have been exported from Spain to the New World, where they acquired Native American and African influences, to be reimported again in Andalusia by returned emigrants.
They include palos such as sevillanas, nanas ("lullabies"), bamba, zambras, zorongo or campanilleros and of course the Spanish Rumba.