[1] The term lehendakari is a 20th-century coinage, from the Basque lehendabizi ("first") and the suffix -ari which indicates a profession.

Before the establishment of Standard Basque in the 1970s, it was spelled Euzko Jaurlaritzaren Lendakari.

On the other hand, the word lehendakari is commonly used in Spanish, both in and outside the Basque region, to refer exclusively to the Basque president, comparable to the use of Taoiseach as the title of the Irish head of government in English.

Lehendakaris elected for the PNV have sworn office following a ritual established by Aguirre: next to the Guernica Tree, on a Bible in Basque, using a symbolic formula which reads "before God, prostrated, standing on Basque land, remembering the ancestors, under the Guernica Tree and before you, representatives of the Basque people, I swear thus, to fulfill the mandate granted to me as Lehendakari, and will thus be duly protecting and respective of the laws of this land".

Former lehendakari Patxi López used a similar formula in the same place, but also included visible changes to it by suppressing the "before God, prostrated" part and the fact that he sworn on a Basque Statute of Autonomy rather than on a Bible.