This is the 4653rd most frequent Spanish word.
castellano
"Castellano" refers to the Spanish language, especially as spoken in Spain or in its traditional form originating from the region of Castile.
In this sentence, 'castellano' refers to the Spanish language in a formal and academic context.
El castellano es una lengua romántica que se habla en muchos países.
Spanish is a Romance language spoken in many countries.
Here, 'castellano' is used to refer to the practical and standard version of Spanish as spoken in several regions.
Estoy aprendiendo castellano para comunicarme mejor en Sudamérica.
I am learning Spanish to communicate better in South America.
In this context, 'castellano' specifically denotes the variety of Spanish spoken in Castile and by extension the standard version of Spanish.