What's an article?

What's an article? I was asking myself this very question in the post office yesterday, standing in line waiting to a sign for, as it so happens, an article. A postal article. Not the postal article. Now before we get ahead of ourselves, an article in English is a verb that precedes a noun, and simply indicates specificity. This sounds quite complicated, and to be honest, it's quite complicated to say without spraying everyone within 15 feet, but the concept's quite simple. The definite article in English is the word "the", and indicates a specific thing or type; for example, the train is an hour late. By contrast, the indefinite article in English is any of the words "a", "an" or "some", and the indefinite article indicates a non-specific thing; for example, would you please pass me an apple. We always preceed a word with "a" if it doesn't start with a vowel sound. For example, take a hike; I'm spending a Weekend at Burnie's; or there's a Knight in Shining Armour. Similarly we process words with the indefinite article "an" if they do start with a vowel sound, for example, an ostrich, an informal mess or an Occupational Health and Safety Policy.