Articles in the English language are ‘short’ words that precede the nouns they modify. Though ‘short’, they are often misused and can create grammatical blunders if incorrectly used. Here is a write-up to guide you on the correct usage of articles.
Articles are a special category of adjectives that are used to indicate definiteness of nouns. These include the and a/an. Before choosing an article, it is important to know whether the noun is definite or indefinite. The article the is used for definite nouns and a and an are used for indefinite nouns.
Definite article (the)
The is the only definite article in English. It is used when the noun has already been specified in the context or when the listener/reader is aware of the noun being referred to. It is used before both singular and plural nouns and is independent of whether the noun starts with a consonant sound or a vowel sound.
Example 1: Did you go to the doctor?
Here, the speaker asks the listener if he visited a specific doctor.
Example 2: Incubation of the test tubes was done at 370 C.
Here, the listener is already aware of the test tubes being talked about.
Example 3: The protein was purified using size-exclusion chromatography.
In this case, readers already know the name of the protein.
Do not use the if the subject has not been introduced before.
Indefinite articles (a/an)
An indefinite article is used when the identity of the noun is unspecified. It is used when the noun is being referred to for the first time or while making a general statement. A is the indefinite article used before a consonant sound and its variant an is used before a vowel sound.
My colleague and I published a research article in the journal, Nature.
My colleague and I published an article in the journal, Nature.
Note the usage of a and an in the above examples; a comes before a consonant, and an comes before a vowel. In addition, the use of indefinite articles a/an introduces the noun (research article or article, in this case) for the first time to the readers.
Use of articles for proper nouns
A proper noun represents a person, a place or a thing and requires capitalization. The article the is used before certain proper nouns such as names of water bodies such as the Atlantic ocean, the Ganges; mountains such as the Himalayas, the Alps; and theories such as the Quantum theory, the Richter scale. Please note that the is not used before names of people, languages, and countries; except countries that use plural form e.g. the United States of America, the United Kingdom, the Republic of China.