Usage and Grammar

Q. Is it an historical novel or a historical novel?

A. In Chicago style, it’s a historical novel. Please see CMOS 5.74: “With the indefinite article, the choice of a or an depends on the sound of the word it precedes. A precedes words with a consonant sound, including /y/, /h/, and /w/, no matter how the word is spelled {a eulogy} {a historic occasion} {a onetime pass}. An comes before words with a vowel sound {an FBI agent} {an X-Files episode} {an hour ago}.”