Compound Words

In principle it’s easy—just put two or more words together to create a new “word”. However, it’s not that straightforward. Following are some guidelines to make sure your writing is as effective as possible.

What’s a compound word?

A compound word is the result of joining two or more words in order to create a new word that has a different meaning than any of the original words. They can be composed of nouns, verbs, adjectives, and adverbs.

Three forms of compound words

1) open—These are separate words with spaces between them (e.g., attorney general, double agent, field trip, full moon, grand jury, ice cream, middle class, post office, real estate)

2) hyphenated—These are separate words with hyphens between them (e.g., cross-examine, eighty-five, good-looking, mass-produced, merry-go-round, one-half, over-the-counter, part-time, son-in-law, well-meaning)

3) closed—This is a single word, with no spaces or hyphens (e.g., anybody, backward, basketball, cannot, crosswalk, earthquake, fireworks, football, forward, grasshopper, inside, moonlight, nobody, proofread, railroad, sideways, skateboard, straightforward, tonight, weatherman).

Evolution of compound words

Compound words may start out as open, then evolve, over time, into a hyphenated form, and then into a closed form. This evolution can take a while or it may happen rapidly, usually based on frequency of usage. Examples:

electronic mail became e-mail, then quickly became email

electronic book is still evolving, with e-book, eBook, and ebook battling for favorite

Note: eBook can be challenging at the beginning of a printed sentence, for obvious reasons (EBook), and ebook is not preferred by many automated spell-checkers. So, this book uses e-book.

A compound word that seems to have skipped the hyphenated stage is web site, which went directly to website.

When in doubt

With an open or closed compound word, the spelling is usually pretty clear. However, with hyphenated compounds, it gets a little more challenging. The issue is permanence—a hyphenated compound word may be a one-time creation, or it may be an intermediate stage between open and closed. So, if you’re in doubt about which of the three forms is currently correct, refer to a current dictionary (you may have to use an electronic version). It’s possible that you won’t find every possible hyphenated word there, but you’ll likely find words that are hyphenated in standard usage.

Location of compound adjectives

Compound adjectives that appear before the noun are usually hyphenated. That’s to make sure that there’s no confusion about the meaning. Example:

He’s a good-looking boy.

Without the hyphen, a reader might wonder what a looking boy was, and wonder if there are also bad versions of looking boys. With the hyphen, the writer is sharing a single characteristic of this boy. When the compound adjective appears after the noun, there’s usually less chance of confusion. Example: The boy is good looking.

Hyphenation rules

The first rule is that you should hyphenate for clarity. If a compound word would create confusion for a reader (i.e., a phrase could be read several ways, as in the example above), it should be hyphenated or simply rewritten.

Long compound words are often best hyphenated (e.g., His better-than-ever-guaranteed plan.).

Compound adjectives with -ly adverbs are not hyphenated (e.g., The man had on badly worn shoes.), unless the -ly adverb is part of a longer phrase (e.g., The ever-so-badly-worn shoes told a sad story.).

Other rules get fairly involved. The Chicago Manual of Style, an excellent and necessary reference for writers, has several pages in section 7.90 devoted to compound word formation. But again, it might be quicker and easier to just consult a current dictionary.


When you’ve determined how to write a compound word, it’s important to be consistent throughout a project. Changing formats would be especially noticeable if you use one style and then, a short distance later in the text, you use another. Many readers tend to notice these things, and will judge a writer (and maybe the editor) accordingly.

Copyright 2019 by Affordable Editing Services

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