Articles in Grammar: From "A" to "The" With "An" and "Some" Between

Dr. Richard Nordquist is professor emeritus of rhetoric and English at Georgia Southern University and the author of several university-level grammar and composition textbooks.

In English grammar, an article is a type of determiner that precedes and provides context to a noun. A determiner is a word or a group of words that specifies, identifies, or quantifies the noun or noun phrase that follows it: There are only two types of articles in English, definite or indefinite. The three main articles in English grammar are "the," "a," and "an." This grammatical concept may sound simple, but there are some tricky rules related to using it correctly.

Definite vs. Indefinite Articles

The only definite article is "the," which specifies a particular individual or thing in a particular context. For example, in the title of a famous Sherlock Holmes story "The Hound of the Baskervilles," the first word of the sentence is a definite article because it refers to a specific case that the illustrious fictional detective tried to (and, of course, did) solve.

By contrast, Purdue Owl notes the indefinite articles—"a" and "an"—signal that the noun modified is indefinite, referring to any member of a group, or something that cannot be identified specifically by the writer or speaker. An example of a sentence containing both the "a" and "an" indefinite articles was published in E.B. White's classic children's tale "Charlotte's Web."

"Mr. Arable fixed a small yard specially for Wilbur under an apple tree, and gave him a large wooden box full of straw, with ​a doorway cut in it so he could walk in and out as he pleased."

This example uses both "a," which is always used before a consonant sound, and "an," which is always used before a vowel sound.

Using "A" and "An"

The key to knowing when to use "a" or "an" depends on the sound at the beginning of the noun (or adjective) that is being modified, not whether the noun or adjective actually begins with a vowel or consonant, notes study.com:

"If the noun (or adjective) that comes after the article begins with a vowel sound, the appropriate indefinite article to use is 'an.' A vowel sound is a sound that is created by any vowel in the English language: 'a,' 'e,' 'i,' 'o,' 'u,' and sometimes 'y' if it makes an 'e' or 'i' sound."

By contrast, if the noun or adjective that comes after the article begins with a consonant that actually sounds like a consonant, use "a." "The Complete English Grammar Rules" presents some examples of when to use "a" or "an," depending on the sound of the first letter of the noun the article is modifying.

• "What anunusual discovery." - This is correct because "unusual" starts with a "u" that makes an "uh" sound.
• "What a unique discovery." - This is correct because the adjective after the article begins with a "u" that sounds like the consonant sound "yu."
• I bought "a horse." - You use the "a" here because "horse" starts with an "h" that sounds like the consonant "h."
• "Ahistorical event is worth recording." - Many folks think it should be "an" historic," but the article "a" is correct because the "h" is pronounced and sounds like the consonant "h."
• "Anhour" has passed. - In this case, you use "an" because the "h" in hour is silent, and the noun actually begins with the vowel sound "ow."

Note that in the first two sentences above, the article actually precedes the adjectives, "unusual" and "unique," but the articles actually modify the noun, "discovery" in both sentences. Sometimes the article directly precedes an adjective that modifies the noun. When this occurs, look at the first letter of the adjective when determining whether to use "a" or "an" and then use the same rules as those discussed above to determine which article to use.

Before Countable and Uncountable Nouns

When dealing with articles, nouns can either be:

• Uncountable - You cannot count a specific number.
• Countable - The noun does indicate a specific number.

When a noun is uncountable, it is preceded by an indefinite article—"a" or "an." Butte College gives this example to illustrate both:

• I ate an apple yesterday. The apple was juicy and delicious.

In the first sentence, "apple" is uncountable because you're not referring to a specific apple; whereas, in the second sentence, "apple" is a countable noun because you are referring to one specific apple.

Another example would be:

• Would you like tea? or "Would you like some tea."
• "I would like the tea."

In the first instance, "tea" is uncountable because you're not referring to a specific tea, but instead, just to "some" tea (an undefinable number or amount). In the second sentence, by contrast, the speaker is referring to a specific cup or bottle of tea.

When to Omit Articles

As the first sentence in the previous example shows, you can sometimes omit the article particularly when the number or quantity is not known. Sometimes you would use the article in American English but not British English. For example:

• "I have to go to the hospital." (American English)
• "I have to go to hospital." (British English)

Conversely, sometimes you omit the article in American English but not in British English, as in:

• "I played rugby." (American English)
• "I play the rugby. (British English)

In these cases, the use, or omission, of the definite article depends on the type of English being spoken.

Pronouns, Demonstratives, and Possessives

You can also replace articles with pronouns, demonstratives, and possessives. They all work in the same way as a demonstrative article—naming a specific thing:

• In English grammar, a pronoun is a word that takes the place of a noun, noun phrase, or noun clause. So, instead of the sentence: "Give the book to me," you would replace the definite article, "the," as well as the noun it modifies, "book," with the pronoun, "it," to yield the sentence: "Give it to me."
• A demonstrative is a determiner or a pronoun that points to a particular noun or to the noun it replaces. So, instead of saying: "The movie is boring," you would replace the definite article, "the," with the demonstrative "this" or "that" to yield: "This movie is boring" or "That movie is boring."
• A possessive pronoun is a pronoun that can take the place of a noun phrase to show ownership. Instead of saying: "The tale is long and sad!" you would replace the definite article, "the," to yield a sentence, such as: "Mine is a long and sad tale!" In the first sentence, the definite article, "the," modifies the noun, "tale." In the second sentence, the possessive pronoun, "mine," also modifies the noun, "tale."

High-Ranking Words

According to Ben Yagoda's book "When You Catch an Adjective, Kill It: The Parts of Speech, for Better and/or Worse," the word "the" is the most commonly-used word in the English language. It occurs "nearly 62,000 times in every million words written or uttered—or about once every 16 words." Meanwhile, "a" ranks as the fifth most commonly used word—and "an" ranks 34th.

So take the time to learn these important words—as well as their replacements, such as pronouns, demonstratives, and possessives—correctly to boost your command of English grammar, and in the process, enlighten your friends, impress your teachers, and gain the admiration of your associates.