The word "español" means "Spanish" in English, and the word "libros" is plural for "libro" and means "books." Even though "libro" always translates the same, the word "español" depends on the context.
"Español" refers to the Spanish language, but the word also defines a person's Spanish nationality. The same word applies to label an object as of Spanish origin. The usage of the word is very similar in both the Spanish and English language. "Libro" and "book" are also very similarly used in both languages, referring to both the actual paper book and the idiom "to keep the books," or "llevar los libros" in Spanish.