"An hour" or "a hour"

Question

Which indefinite article should precede hour — a or an?

• an hour
• a hour

Does the usage of an vs a depend on the pronunciation — a history, a hobby, but an hour, an honor?

Answer 1

Does the usage of an vs a depend on the pronunciation: a history, a hobby, but an hour, an honor.

Yes. If a word begins with a vowel sound, then the correct article is an; otherwise, if it begins with a consonantal sound, the correct article is a.

Because hour is typically pronounced with a silent h, an hour is correct.

I wrote a blog post about an vs a on the EL&U blog some time ago, and it covers a wide variety of other cases that you might be interested in.

Answer 2

An hour is correct, because "hour" begins with a vowel sound. A vs. an depends on pronunciation, not spelling.

Some notable cases:

• A/an NIC (network interface card)--proper spelling depends on prounuciation... "A nick" vs. "an N-I-C"
• A/an herb. "An erb" in many cases/regions. "a herb" (with pronounced H) in some

Answer 3

You are correct in your assumption. The usage does depend on the pronunciation. If the subsequent word starts with a vowel sound, then the previous word must be an. If the word starts with a consonant sound, then the previous word is a.