A compound noun contains two or more words which join together to make a single noun. Compound nouns can be words written together, words that are hyphenated, or separate words that go together by meaning.
Most compound nouns contain at least one noun. The other word or words may be an adjective, preposition, or verb. The second word is almost always the main word, with the first word modifying it or adding to its meaning.
Compound words, a large group of words to which compound nouns belong, are expressed in three ways. The closed form has two words that have melded together to make one word, like: softball, redhead, makeup, and keyboard. Examples of the hyphenated form are: six-pack, five-year-old, and son-in-law. The open form has the words next to each other, like: post office, upper class, and attorney general. Sometimes, the hyphen disappears as the word is more widely used, and it becomes a closed word.
Here are types of compound words and examples. The asterisks indicate types of compound words that may be compound nouns.
There are no hard and fast rules concerning plurals of compound words, especially since some hyphens are omitted after time. In hyphenated words, usually the “s” goes at the end of the main word, like daughters-in-law or mayors-elect. Sometimes it is at the end, like in go-betweens and higher-ups. In the open form, the “s” is added to the main word, like: bills of fare, assistant secretaries of state, and notaries public.
To make a compound word possessive, you usually add an apostrophe “s” at the end of the word, like: mother-in-law’s car or five-year-old’s birthday. If the compound word is plural, it can get a little strange with two “s” sounds close together, like: “fathers-in-law’s attire”. If you can, it would be better to reword the sentence so the plural compound word does not need to be possessive, like: “The attire of the fathers-in-law.”
Nouns can be classified in five ways by the characteristics of the objects they represent. If the objects can be counted, they are “count” or “countable” nouns. “Mass” or “uncountable” nouns refer to something that has mass but no parts to count or too many to count. Nouns that refer to a group of people or things are called “collective” nouns. “Concrete” nouns can be experienced with the senses of taste, smell, touch, hearing, and sight. On the other hand, “abstract” nouns can not be experienced in this way. Here are some examples of these types of nouns:
Nouns have several functions in sentences. They can be the subject, an object, an appositive, or a complement. Following is a brief explanation of these functions.
A noun as a subject of a sentence tells who or what is performing an action. The subject is who or what the sentence is about, as in “Horses are pretty.”
A noun can be an object of a preposition, like “in the house”. It can be a direct object, like: “The dog bit Harry.” It may be an indirect object, like “I gave Sarah the book.”
An appositive is a word that renames a noun that it is adjacent to, such as: “Suzie, my dog, ran down the street.”
A noun can be an object complement, which follows the noun or pronoun it modifies. An example is “We elected him mayor.” Lastly, a noun can complement a subject, as in “That dog is a mutt.”