Definite and Indefinite Articles

To decide if an article is needed before a noun or which one to choose, ask yourself the following question:



Articles in Academic Writing

The flowchart with questions can be complemented with the classification below, in which more nuanced explanations of articles are provided. This fairly non-traditional classification comes from Caplan, N. (2015). Grammar Choices for Graduate and Professional Writers. University of Michigan Press.

Articles determine or specify whether a noun is general or specific in its references. The questions we ask to determine if the noun is general or specific are: is it all things (generic reference), one of many things (indefinite reference), or this one thing (definite reference)? Below is the detailed explanation of the three types of references.

Generic Reference

Nouns that describe a class, not an individual person or thing, have generic reference; the meaning of the noun is all of it/them. Generic reference can often be seen in general statements used to introduce, define, or summarize ideas.



Non-Count Nouns

Use no article for generic reference.


The development of a testable hypothesis is a key characteristic of good science.

Count Nouns

1.     Use a plural noun (with no article). This is the most common use for generic reference.


2.     Use a/an + singular noun, especially in definitions.


3.     Use the + singular noun as an alternative with humans, animals, organs of the body, plants, and complex inventions. It is used only in formal contexts.


1.     The process can be intensely demoralizing both for students and teachers.

2.     A portfolio is a file containing samples of a child’s work.

3.     The basic structure of the brain is affected by the sum of the adolescent’s experiences with his or her environment.

Indefinite Reference

Indefinite reference is appropriate when the reader and/or the writer do not both know the specific identity of the noun. This might be because:

  • it is not important (use a computer = use any computer)
  • not known to the writer (a further study is needed)
  • new to the reader (we used a new technique = the writer knows exactly which technique, but the reader does not).

The basic meaning of a noun with indefinite reference is one/some of many.



Singular Count Nouns

Use a/an for all singular count nouns with indefinite reference. Remember to use an when the next word starts with a vowel sound.

Prior to the 1940s, the teaching of ESL was not regarded as a profession in the United States.

[A profession here means “any profession” so the noun is indefinite].

Non-Count Nouns and Plural Nouns

No article is used when the non-count noun or plural noun is with an indefinite reference.

The presence of ESL students should be an important consideration for all teachers and scholars of writing because ESL students can be found in many writing courses across the United States.

Special Uses

1. Expression of quantity

2. The meaning of per


1. a number of, a piece of, a section of

2. 60 miles an hour, $200 an hour

It is important to mention that there is really difficult to identify the difference with generic reference and indefinite reference with plural and non-count nouns; however, it is not necessary since they have the same grammatical rules.

Definite Reference   

A definite reference is used when the reader and writer both know or can easily find the exact meaning of the noun. Academic writers use definite reference extensively to connect ideas within and between sentences and to establish sheared knowledge with readers. All common nouns (count and non-count, singular and plural) use the for definite reference. A noun is definite if:



It has been previously identified in the text.

Payne et al. conducted their first cross foster experiment in 1998: Payne and his colleagues performed the experiment with Vidua chalybeata, the village indigobird.

[The experiment is definite because it was introduced in the first sentence].

It is unique (if there is only one of something, it is fully identified for the reader).

Constant littering has a large negative impact on the environment.

The noun phrase includes a superlative adjective, which is necessarily unique (the first, the second, the next, the only, etc.).

The biggest problem with conducting the study was a lack of a control group.

The noun is identifiable due to a modifier or quantifier.

the U.S. government, the problem of college, the people who supported the association

The noun is part of a whole group.

The agricultural sector accounts for about one-fourth of the country’s Gross Domestic Product, two-fifths of the country’s exports, and half of the labor force.

Some proper nouns require definite articles, including some countries or territories that are or were comprised of smaller units.

the Atlantic Ocean, the Antarctic, the White House

the United States, the United Kingdom, the Philippines, the Soviet Union

Another rare exception to the general pattern of not using any articles with proper nouns is to suggest that a person or organization changed over time. These nouns must be qualified with a restrictive relative clause or prepositional phrase. 

Europe is not today what it was when President Bush took office, and it scarcely resembles the Europe that President Bill Clinton claimed to know. [The writer distinguishes between Europe today and the Europe of the past].


Read this passage and fill in the blanks with either a, an, the, or no article.

Much has been learned about _____ brain in ____last 150 years. _____ brain, most complicated organ of ______ body, contains _____ ten billion nerve cells and is divided into ____ two cerebral hemispheres, one on _____right and one on ______left. Interestingly, ____ left hemisphere controls _____ movements on ______right side of ______body, while _____ right hemisphere controls_____ movements on _____ left.

            ______ researchers also know that______ specific abilities and behaviors are localized; in ____other words, they are controlled by ______specific areas of _____ brain. _____language, it seems, is highly localized in ______ left hemisphere. In_____1860s, Dr. Paul Broca discovered that _____damage to _____front left part of _____brain resulted in_____telegraphic speech similar to that of young children. Soon thereafter, Karl Wernicke found that _____ damage to _____ back left part of_____ brain resulted in ______speech with_____ little semantic meaning. These two regions in______brain are now referred to as _____Broca’s area and Wernicke’s area.

            Although there is some debate surrounding _____ specialization of the brain, researchers generally agree that _____ speech is controlled by _____left side. There is no debate that in_______ great majority of cases, ______ injuries to ______ left side nearly always have ______impact on ____speech.

Exercise adapted from Swales, J. M., & Feak, C. B. (2004). Academic writing for graduate students: Essential tasks and skills. Ann Arbor, Michigan: University of Michigan Press.

Last updated 7/16/2018