A Versus An
The rule for using "a" and "an" is actually more complicated than you may have been taught.
A Historic or an Historic
While we’re talking about different pronunciations, let’s talk about a historic. Some Americans argue that it should be an historic, but I come down firmly on the side that says it should be a historic event. One of the most contentious interactions I had at a book signing was over this point.
Here’s my reasoning: If you have an odd accent for an American and pronounce historic as “istoric,” you can make an argument for writing an historic, but it’s a stretch since the standard American pronunciation of historic is with the h-sound: “historic.” So even if you pronounce it “istoric,” most of your readers won’t.
If you’re feeling argumentative about this point, I’ll direct you to Bill Walsh’s website, The Slot, which has an exhaustive review of how different style guides deal with this word. But you should know that after reviewing many style guides, he also stands behind a historic being the correct choice.
For more on this topic, I address the word "historic" in greater depth in this post.
Definite and Indefinite Articles
A and an are called indefinite articles. The is called a definite article. The difference is that a and an don't say anything special about the words that follow. For example, think about the sentence, “I need a horse.” You'll take any horse—just a horse will do. But if you say, “I need the horse,” then you want a specific horse. That's why the is called a definite article—you want something definite. At least that's how I remember the names.
- Faigley, L. The Little Penguin Handbook. New York: Pearson Education. 2007, p. 255.
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