Castilian

Short definition from Wiktionary

Proper noun

1. 1
   The Castilian dialect of Spanish, often (especially historically) considered the prestige dialect of Spanish.
2. 2
   Synonym of Spanish, the language of Spain and its former colonies.

Noun

1. 1
   A native of Castile.

Adjective

1. 1
   Of, from, or relating to Castile.