Definitions for "castilla"
a region of central Spain; a former kingdom that comprised most of modern Spain and united with Aragon to form Spain in 1479
Castilla (sometimes incorrectly spelled Castilloa) is a tree genus belonging to the family Moraceae found native in Central America. The main species is Castilla elastica, one of several plants from which rubber has been extracted. The vernacular name is Panama rubber tree or castilloa rubber.