The Standard Definition of a Noun
Many people define a noun simply as a word that names a person, place, thing, or concept (e.g., Tom, library, monkey, and freedom).
However, not all such words are always nouns.
For example, depending on how it is used in a sentence, monkey might not be a noun. In the phrase, “The kids often monkey around,” monkey is a verb. And if someone asks you to pass them a monkey wrench, they’ve used monkey as an adjective.
Three Types of Nouns
A good place to begin discussion about what actually makes a word a noun is with a quick explanation of the three types of nouns. Nouns can be categorized into three basic groups: common nouns, proper nouns, and pronouns.
A common noun is a word used to identify a person, place, or thing (e.g., girl, tower, movie). However common nouns do not give the name of one specific person, place, or thing. That is the job of a proper noun (e.g., Rosie, the Eiffel Tower, Back to the Future). A person, place, or thing can also be identified by using a pronoun. A pronoun is a single word that substitutes for either a common noun or a proper noun (e.g., I, he, she, it, they).
Properties of Nouns
It is not entirely accurate to classify a word as a noun simply because it names something. A more precise definition is needed. A noun should be thought of as a word that, given its purpose in a sentence, has most or all of the properties of nouns,¹ which are as follows:
A noun can be pluralized without making a sentence confusing.
The sentences, “The monkey climbed up the tree,” and “The monkeys climbed up the tree,” both make perfect sense. This is an indicator that monkey is a noun as it is used in this sentence.
Monkey cannot be pluralized in “The kids often monkey around.” “The children continued to monkeys around” is an ungrammatical expression.
A noun can be preceded by the articles “the” or “a.”
Our example, “The monkey climbed up the tree,” shows this property in action. If a word cannot be preceded by the in a phrase, that word is probably not a noun. Monkey cannot be a noun in “The kids often monkey around” because “The kids often the monkey around” is not proper English.
It is important to note that the word the or a does not need to immediately precede a noun for the noun to have this property. Often, adjectives are placed between articles and their corresponding nouns, such as in “The short, hairy monkey climbed up the tree.”
This property is sometimes tricky to spot. For instance, in the phrase, “The monkey wrench was too small for the job,” it might appear as though monkey is a noun because it is preceded by the. However, monkey is an adjective in this sentence. Notice that the first property of nouns does not apply to monkey this phrase — “The monkeys wrench were too small for the job” is incorrect.
A noun can be preceded by adjectives.
We will again look at the sentence, “The monkey climbed up the tree.” Monkey is a noun because it can be modified by adjectives, as in the example we saw earlier: “The short, hairy monkey climbed up the tree.” Monkey cannot be a noun in “The kids often monkey around” because it is not grammatically correct to put adjectives in front of it. “The kids often short, hairy monkey around” is nonsense.
As with the previous property, this one can be deceiving sometimes, as words that are not nouns occasionally appear to be preceded by adjectives. In the sentence, “They would slow dance to their favorite song,” it looks like dance follows an adjective (slow). However, dance is a verb in this sentence because “They would a slow dance to their favorite song” and “They would slow dances to their favorite song” are improper English. Because dance is not a noun in this sentence, slow is not an adjective but rather an adverb.
A noun functions as the head of a noun phrase.
An example of a noun phrase is “the small, funny monkeys” as it appears in “We watched the small, funny monkeys.” We can be sure the underlined string of words in this sentence is a noun phrase because all of these words describe the noun monkeys (which we know is a noun because it is pluralized and preceded by adjectives and the word the).
If we strip all the words except for monkey from the phrase, the sentence retains its meaning, simply with less detail: “We watched monkeys.” Sentences that contain other segments from the noun phrase do not make sense: “We watched the funny.” Thus, it is without question that the string of words revolves around the word monkeys. For this reason, we say that monkeys is the head of this noun phrase.
Any word that serves as the head of a noun phrase is always a noun even if it does not have all of the other characteristics of a noun. Conversely, if a word does not head a noun phrase, it is not a noun even if has other characteristics of a noun. Because of this, proper nouns and pronouns are considered nouns even though they often do not have all the properties of nouns.
Proper Nouns vs.Pronouns
Proper nouns have only the third and fourth properties of nouns from the list given above. Meanwhile, pronouns have only the fourth property. Nonetheless, this is enough to make these words nouns according to most grammarians.
The proper noun John is a noun in “Big John plays baseball.” John is the head of a noun phrase in this sentence, and so John is a noun even though “The big John plays baseball” and “Big Johns play baseball” are not grammatical.
The pronoun he, by itself, is a noun phrase in the sentence, “He plays baseball.” Therefore, he is a noun in this sentence even though “The he plays baseball,” “Hes play baseball,” and “Big he plays baseball” are all incorrect.
Because pronouns share so few properties with nouns, some view pronouns as being a part of speech of their own rather than being a subgroup of the noun word class. The next article in this series discusses pronouns in detail.
Nouns that Don’t Look Like Nouns
We now have a more accurate idea of what a noun is, and we can classify more words as nouns than we would if we were to use the standard definition given at the beginning of this article. For instance, consider the word run, which as an “action word” is generally thought to be a verb.
Prior to reading this article, you may have thought the word run is a verb in the sentence, “I will not have time for a run.” However, run is a noun in this sentence. Notice that it has all the properties of a noun:
Run can be pluralized without creating an ungrammatical sentence: “I will not have time for runs.”
Run is preceded by an article: “I will not have time for a run.”
Run could have adjectives placed in front of it: “I will not have time for a long, grueling run.”
Run is the head of the noun phrase, “a run.”
To simply define a noun as a word that names a person, place, thing, or concept is not always accurate. Hopefully, this article has shown you how to identify nouns in any sentence and how to avoid misidentifying other kinds of words as nouns.
¹Pronouns and proper nouns are exceptions — they are nouns despite not having most of these properties