What is a Compound Word?

Tricia Christensen
Tricia Christensen

Words such as "airplane," "newspaper," or "paperclip," contain two distinct words that function separately but have been placed together. Joining these two independent words creates a compound word, which may have a new meaning or simply a more precise definition. "Air" and "plane" come together to form "airplane," while "paper" and "clip" become "paperclip." These words can be formed either as a solid term or using a hyphen; non-standard phrases are often created as descriptive words or adjectives.

Paperclip is a compound word.
Paperclip is a compound word.

Meaning and Purpose

A compound word is, simply, two words joined to make a new and often more specific word applicable to a particular circumstance. For instance the word "news" can mean many things, though it usually refers to the delivery of current information. When combined with the word "paper," which could also refer to several different things, the compound word, "newspaper," is formed and refers to a specific object. Similarly, a "paperclip" is a particular type of clip intended for a specific purpose.

Newspaper is a compound word.
Newspaper is a compound word.

Typical Usage

It is important to understand the use of compound words because some of them may have different definitions when the words are joined, rather than merely used consecutively in a sentence. This distinction is vital to ensuring proper meaning in a statement. For example, the compound word "overall" takes on a slightly different meaning than the two words "over all" in a sentence.

This can be seen in the two following sentences: "Overall, I enjoyed the film," and "The film was picked over all the others to win an award." In the first example, "overall" is a transitional word that sums up the thoughts of the speaker. It could be used as a synonym for terms like "in conclusion." In the second example, however, the words "over all" imply "above all the others" or "over all the others;" this usage means something is superior to something else, rather than a summation.

Basic Structure

When someone joins two words together to form a compound word, the spelling of those words does not usually change. Instead, the major change is simply a deletion of spaces between the words. It is, in essence, a marriage of words, where two become one.

There are some exceptions to this rule of marriage. Just as many women prefer a hyphenated last name when they get married to keep their maiden names, some compound words may be hyphenated instead of being joined directly together. Compound words not joined by a hyphen are called "closed" compounds, while words joined by a hyphen are "hyphenated" compounds. There is also an "open" form for a compound word such as "post office," in which the space is not deleted but the two words function as one.

Hyphenated and Closed Compounds

When choosing whether to join words, either by hyphen or deletion of space, a writer should consult a dictionary for the correct structure. There are many words that may be compounded, and sometimes it can be difficult to determine how they should be joined and in what context it is appropriate to do so. Generally, when someone joins two words that are not usually compounded, the writer uses a hyphen to express a relationship, instead of creating a compound word that does not actually exist. This is often done for words that are used together to create an adjective such as "well-known" or "bright-red."

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent wiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments


@StarJo – It depends on which stylebook guide you use. Chicago and AP are different in several ways, and I choose to use the AP stylebook.

The AP guide lists “cellphone” as one word. Also, “smartphone” is a closed compound word now.

I also noticed that they have removed the hyphen in the word “e-mail.” The correct way to write it is now “email.”


I still remember learning about compound words and compound sentences in elementary school. It was an easy concept for me to grasp, but other kids had trouble with it.

Any time you are compounding something, you are putting one thing with another. So, it was easy for me to remember how to translate this into grammar.


It can be hard sometimes to tell which words should be written as closed compounds and which should be left open. While I've known that “post office” is an open compound all my life, there are other compounds that are kind of ambiguous.

For example, some people lump the words “cell” and “phone” together to make one word. Others leave the word cell phone as an open compound.

Also, I've seen “counter” and “top” split into two words, but I've also seen them combined. It is hard to know which is the correct way in situations like this.


I do hyphenate words to form compound words sometimes, but I've never put a hyphen between “bright” and “red.” I always thought that “bright” was an adjective describing red, so there was no hyphen needed.

However, if I'm joining two colors, I will put a hyphen between them. If I want to say that something is blue-green or orange-red, I will always use a hyphen.


very good and helpful article.


Good post. Needs many more examples. thanks!


It is very useful for learner of language. This article has helped me to grasp the nature of compound words.I think some more examples would have made it rich. Thanks.


This article is very good! It is really helpful! I have to thank you for this article!


this was a very good article.

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