[1] The word refers both to one of the four sub-regions of the Northeast Region of Brazil or the hinterlands of the country in general (similar to the specific association of "outback" with Australia in English).

[2][3] Northeast Brazil is largely covered in a scrubby upland forest called caatingas, from the Tupi language, meaning white forest, since leaves fall during dry season, donning all vegetation, mainly bushes and small trees, now reduced to bare branches and trunks, in its characteristic very light grayish, or off-white, hues.

[1] A Brazilian historian once referred to colonial life in Brazil as a "civilization of crabs", as most settlers clung to the shoreline, with few trying to make inroads into the sertão.

In modern terms, "sertão" refers to a semi-arid region in northeastern Brazil, comprising parts of the states of Alagoas, Bahia, Pernambuco, Paraíba, Rio Grande do Norte, Ceará, Maranhão, Piauí, Sergipe, and Minas Gerais.

[7] The immortal of the Brazilian Academy of Letters Gustavo Barroso also rejected this hypothesis and argued that the origin of the word was in the term muchitum, from the Mbunda language of Angola, which means "place in the interior".

The term would have been adopted by the Portuguese colonizers in the form of "mulcetão", later reduced to "celtão" and "certão", and then spread throughout the Lusitanian overseas empire during the first centuries of its expansion.

On one occasion when enemy troops attacked the settlement, a woman defended herself from the soldiers with a large sertãa, a square frying pan, saving the village.

In its natural state, the sertão was covered by a distinctive scrubby caatinga vegetation, consisting generally of low thorny bushes adapted to the extreme climate.