There are several ways to classify the types of nouns that exist in the English language. In traditional grammar, nouns are taught to be words that refer to people, places, things, or abstract ideas. While modern linguistics find this definition to be problematic because it relies on non-specific nouns such as thing to specifically define what a noun is, much of our social understanding of what nouns are defers to the traditional definition.
Proper nouns are nouns that refer to specific entities. Writers of English capitalize proper nouns like Nebraska, Steve, Harvard, or White House to show their distinction from common nouns.
Common nouns refer to general, unspecific categories of entities. Whereas Nebraska is a proper noun because it signifies a specific state, the word state itself is a common noun because it can refer to any of the 50 states in the United States. Harvard refers to a particular institution of higher learning, while the common noun university can refer to any such institution.
A compound noun contains two or more words which join together to make a single noun. Compound nouns can be words written together (closed form) such as softball and toothpaste, words that are hyphenated (hyphenated form) such as six-pack and son-in-law, or separate words (open form) such as post office and upper class that go together by meaning.
To linguists, these count nouns can occur in both single and plural forms, can be modified by numerals, and can co-occur with quantificational determiners like many, most, more, several, etc.
For example, the noun bike is a countable noun. Consider the following sentence:
There is a bike in that garage.
In this example, the word bike is singular as it refers to one bike that is presently residing in a particular garage.
However, bike can also occur in the plural form.
There are six broken bikes in that garage.
In this example, the noun bikes refers to more than one bike as it is being modified by the numeral six.
In addition, countable nouns can co-occur with quantificational determiners.
In that garage, several bikes are broken.
This sentence is grammatical, as the noun bike can take the modification of the quantificational determiner several.
Conversely, some nouns are not countable and are called uncountable nouns or mass nouns. For example, the word clutter is a mass noun.
That garage is full of clutter.
This sentence makes grammatical sense. However, the following example does not.
That garage is full of clutters.
Mass nouns can not take plural forms, and therefore a sentence containing the word clutters is ungrammatical.
Substances, liquids, and powders are entities that are often signified by mass nouns such as wood, sand, water, and flour. Other examples would be milk, air, furniture, freedom, rice, and intelligence.
In general, collective nouns are nouns that refer to a group of something in a specific manner. Often, collective nouns are used to refer to groups of animals. Consider the following sentences.
Look at the gaggle of geese. There used to be herds of wild buffalo on the prairie. A bevy of swans is swimming in the pond. A colony of ants live in the anthill.
In the above examples, gaggle, herds, bevy, and colony are collective nouns.
Concrete nouns are nouns that can be touched, smelled, seen, felt, or tasted. Steak, table, dog, Maria, salt, and wool are all examples of concrete nouns.
Can I pet your dog? Please pass the salt. Your sweater is made of fine wool.
Concrete nouns can be perceived by at least one of our senses.
More ethereal, theoretical concepts use abstract nouns to refer to them. Concepts like freedom, love, power, and redemption are all examples of abstract nouns.
They hate us for our freedom. All you need is love. We must fight the power.
In these sentences, the abstract nouns refer to concepts, ideas, philosophies, and other entities that cannot be concretely perceived.
Personal pronouns are types of nouns that take the place of nouns when referring to people, places or things. The personal pronouns in English are I, you, he, she, it, and they.
Amy works at a flower shop. She works at a flower shop.
The Greeks invented democracy. They invented democracy.
These pronouns take on other forms depending on what type of function they are performing in a sentence. For example, when used to signify possession of another noun, pronouns take on their possessive form such as mine, ours, hers, and theirs.
That pizza belongs to Marley. That pizza is hers.
When used as the object of a preposition, pronouns take on their objective case. Examples include him, her, me, us, and them.
Hand the money over to Jennifer. Hand the money over to her.
The police are on to John and Ray. The police are on to them.
Bottomline: There are nine types or classifications of nouns, each designed to serve a different purpose in a sentence.