Ayuntamiento
Ayuntamiento is the general term for the town council, or cabildo, of a municipality or, sometimes, as is often the case in Spain and Latin America, for the municipality itself. Ayuntamiento is mainly used in Spain; in Latin America alcaldía is also for municipal governing bodies, especially the executive ones, where the legislative body and the executive body are two separate entities. In Catalan-speaking parts of Spain, municipalities generally use the Catalan cognate, ajuntament, while Galician ones use the word concello, Astur-Leonese conceyu and Basque udaletxea. Since ayuntamiento is a metonym for the building in which the council meets, it also translates to "city/town hall" in English.
Historically
With the eighteenth-century Bourbon Reforms in New Spain, which created intendancies and weakened the power of the viceroy, the ayuntamientos "became the institution representing the interests of the local and regional oligarchical groups then setting deep roots into their territories." The Spanish Constitution of 1812 called for the transformation of the ayuntamiento, previously dominated by elites, into a representative institution with elections. Article 310 called for the establishment of an ayuntamiento for all settlements with 1,000 inhabitants.The term ayuntamiento was often preceded by the word excelentísimo, when referring to the council. This phrase is often abbreviated "Exc.mo Ay.to ". Other names for ayuntamiento have been casa de cabildo, casa capitular, casa consistorial and casa del concejo.