Scientific Editing Services, Manuscript Editing Service
中文 繁體中文 English 한국어 日本語 Português Español

The Differences between Indefinite Articles (a/an) and Definite Articles (the)

Today I’ll discuss one of the confusing aspects of English grammar for non-native English speakers and writers: the use of articles. What is an article? An article is adjective that modifies (provides more information about) a noun.

The good news (hooray!): the English language only has two articles: the and a/an. The article “the” is used to refer to specific nouns. The indefinite article “a/an” is used to modify non-specific or non-particular nouns. We call “the” the definite article and “a/an” the indefinite article because they serve different functions and provide different kinds of information about the noun they modify. Again, here’s a quick run-down:

the = definite article

a/an = indefinite article

Let’s start with an example:

What’s wrong with the following sentence?

“Researcher I spoke to studied genome sequencing.”

Although this sentence sounds okay, it is missing the definite article (the). Here we are talking about one specific researcher (the one I spoke to); therefore, the article “the” should be used before singular and plural nouns when the noun is specific.

You may now be wondering “when do I use a/an?” The indefinite article “a/an” is used when referring to any member of a group (nonspecific, indefinite); in this case it is not important which particular one we are referring to.

“I want to obtain a new pipette”

In this example it is not important which specific pipette we are referring to; there are many pipettes in the world, we just want one (it doesn’t matter which particular one).

However, note that if you state “I want to buy the pipette I used in the lab yesterday” you are referring to a specific pipette (the one you used in the lab yesterday); therefore, you would need to use “the” (definite article).

Please note: there are times when use of articles is incorrect. Sometimes you don’t need to use them at all.

Articles are not used with plural nouns, uncountable nouns, or geographical nouns. Here are examples with explanations:

Uncountable nouns: "Research is lacking in this subject area." – Research (used here) is an uncountable noun (a mass noun). No article is needed before the word “Research” here.

Plural nouns: “Cells need oxygen.” We are referring to cells (plural noun) in general in this particular sentence, so no article is needed.

However, if you state “The cells in this study required additional oxygen” you are referring to specific cells used in your study; therefore, use of the definite article “the” is needed here.

Specific geographical nouns: Do not use articles with certain geographical nouns i.e. the names of people or places. For example, “Research is being conducted in the Spain” is incorrect because “the” is not needed before Spain (the country, a geographical noun).

*Note: articles are used in these specific instances: the Netherlands, the Dominican Republic, the Philippines, the United States.

*Final note: there are also some kinds of common nouns that don’t take articles:

Names of languages and nationalities: Russian, Spanish, English, Chinese (unless you are referring to the population of the nation: "The Spanish are known for their warm hospitality.")

Names of sports: running, volleyball, hockey, baseball, soccer, football

Names of academic subjects: engineering, linguistics, mathematics, biology, history, computer science

(Please retain the reference in reprint:

Contact us

Contact us  

Your name*

Your email*

Your message*

Please fill in all fields and provide a valid email.