What is Alcalde?

Legal Definition
Alcalde (/ælˈkældi/; Spanish: [alˈkalde]), or Alcalde ordinario, is the traditional Spanish municipal magistrate, who had both judicial and administrative functions. An alcalde was, in the absence of a corregidor, the presiding officer of the Castilian cabildo (the municipal council) and judge of first instance of a town. Alcaldes were elected annually, without the right to reelection for two or three years, by the regidores (council members) of the municipal council. The office of the alcalde was signified by a staff of office, which they were to take with them when doing their business.

Additionally, alcalde was a title given to Indian officials inside the Spanish missions, who performed a large variety of duties for the Franciscan missionaries.
-- Wikipedia
Legal Definition
The name of a Judicial officer in Spain, and in those countries which have received their laws and institutions from Spain. His functions somewhat resembled those of mayor in small municipalities on the continent or justice of the peace in England and most of the United States. Castiilero v. In S., 2 Black, 17, 194, 17 L. Ed. 360.
-- Black's Law Dictionary
Legal Definition
A Spanish officer having judicial powers similar to those of a justice of the peace. See 67 U. S. 17, 17 L. Ed. 360.
-- Ballentine's Law Dictionary