Language Arts Compound words are formed of at least two whole words put together to mean just one thing. Read this article to see examples of compound words and learn more about what a compound word is and when a compound word is open, closed, or hyphenated.

There are words that have a root with a prefix, suffix, or both,. Some words have a root with multiple prefixes and/or suffixes. But none of these are compound words, no matter how long they are. Compound words are composed of at least two whole words, but may also have prefixes and suffixes. Despite containing two words, they mean just one thing, something different than the words mean alone. To learn more about the ins and outs of compound words, keep reading.

Thinking About Compound Words

Compound words are so prevalent in our language that many times we don't even notice them. Words like baseball, vice president, French fries, apple pie, and eight-year-old go right past us without calling attention to the fact that they are compound words. For most of us, it's only when we need to write them correctly in some formal context that we would stop to think about just how they're put together.

There are at least two different ways to think about the types of compound words that there are. We can look at the types of words that go into them - that is, analyze them by what they mean - or we could look at the three different ways they are written - analyze them by their orthography.

Types of Compound Words: Connections

There are three ways of spelling compound words:

Closed compounds In closed compounds the words are juxtaposed with no space between them.

Open compounds In open compounds there is a space between the words.

Hyphenated Compounds Hyphenated compounds are connected by a hyphen (sometimes called a dash).

Here are some examples of each of these three types of compound words:

Closed Compound Words	Open Compound Words	Hyphenated Compound Words
sunrise	ice cream	one-half
beeswax	grand jury	bull's-eye
townspeople	cave in	mother-in-law
aircraft	school teacher	eighty-six

If you read through these words, you will notice that - however they're spelled - in each case the multiple words work together to name just one thing. It's true that a school is one thing and a teacher is another. But a school teacher is a single entity.

Types of Compound Words: Meaning

Another way of thinking about compound words is meaning groups that have similar spellings. There are many different possible combinations, and there isn't room in this article to treat all of them but here are some examples, chosen from those that have a consistent pattern (note that not all compounding words behave consistently):

Age Age terms can be adjectives or nouns, but are hyphenated compounds in both cases:

• Noun: a forty-three-year-old
• Adjective: a forty-three-year-old pilot

Color Color terms that are not old standards are open compounds (black-and-white is an example of one of the old standards, and it's hyphenated).

• reddish purple
• navy blue
• burnt sienna
• blue and green

Compass Points Compass points are closed up when there are two of them; when a third is prefaced, it's added with a hyphen.

• northwest
• west-northwest

Measurements When a number and a unit of measure are combined, they're hyphenated when they appear before a noun and open when they appear in other situations.

• three-ounce glass, but glass that holds three ounces
• two-page memo, but memo with two pages
• hundred-yard dash, but run for a hundred yards

Relationships by Marriage In-laws are always hyphenated.

• brother-in-law
• father-in-law

Compound Words in Documents

It's a good idea to take a little time to check compound words in any written documents you produce. There are at least two important things to check:

• Check line breaks and page breaks to ensure that compound words - especially open compounds - aren't split across them: this kind of split can lead to misreading.
• When breaking a closed or hyphenated compound at the end of the line, follow these principles:

1. If you're breaking a closed compound at a line break, break it at the division between the words whenever possible. Manually move both words to the following line or page when necessary to avoid misreading.
2. If you're breaking a hyphenated compound at a line break, break it at the hyphen whenever possible. Manually move both words to the following line or page when necessary to avoid misreading.