Using Articles in English Grammar: Indefinite (A, An) and Definite (The)

Answer the four questions in the chart to determine the appropriate article to use in English.  Move across and down the chart to determine the answer.

1. Is your noun countable or noncountable?

Countable nouns are items that can be counted.  For example, 2 microscopes, 5 humans, 3 hours.

Noncountable nouns are items that cannot be counted.  For example, research, literature, equipment, information.

2. Is your noun singular or plural?

Examples of singular nouns include a microscope, a human, an idea, or an hour.

Examples of plural nouns are microscopes, humans, ideas or hours.

3. Is the noun general* or specific**??

*Your noun is general if the reader hasn't been introduced to the noun yet.  For example, "He bought a microscope at the store," or "He conducted research on water management systems." 

**Your noun is specific if the reader already knows about the noun, either because (a) you referred to it before: "He bought a microscope at the store; he then gave the microscope to his lab partner;" (b) it has a specific description: "He bought the Meiji microscope that she recommended," or "He conducted the research for which he had been given funding;" or (c) there is only one: "The sun rises at 6:00am."

If your noun is countable, singular and general, then your article should be...

A (Indefinite article) for nouns that start with a consonant or a consonant sound.  For example, a microscope, a human.

An (Indefinite article) for nouns that start with a vowel or a vowel sound.  For example, an idea, an hour.

If your noun is countable, singular and specific, then your article should be...

The (Definite article).  For example, the microscope, the human, the idea, the hour.

If your noun is countable, plural and general, then your article should be...

No article.  For example, microscopes, humans, ideas, hours.

If your noun is countable, plural and specific, then your article should be...

The (Definite article). For example, the microscopes, the humans, the ideas, the hours.

If your noun is noncountable, singular and general, then your article should be...

No article.  For example, research, literature, equipment, information.

If your noun is noncountable, singular and specific, then your article should be...

The (Definite article). For example, the research, the literature, the equipment, the information.