Compound Words—What Are They? (2024)

What Are Compound Words?

What do a honeybee, butterfly, earthworm, and jitterbug have in common? That they’re all insects? Nope! That they’re compound words. We’ll teach you everything you need to know about compound words, from what they are to the different types.

Think of the word fire. You might be picturing something similar to flames of bright light, heat, and smoke. Now, think of the word fighter. You’re most likely thinking of something or someone that fights, like a boxer or soldier. Now, put these two words together: firefighter. What do you imagine? A person whose career is to put out and extinguish fires. This is an example of a compound word—two words with separate meanings combined to create an entirely new word.

Types of Compound Words

There are a few types of compound words, including:

• Compound nouns
• Compound adjectives
• Compound verbs

These can be written as either open, closed, or hyphenated compounds. Open compounds are compounds that have a space between each word (e.g., full moon). Closed compounds don’t have a space (e.g., daybed), and hyphenated compounds have a hyphen separating each word (e.g., up-to-date).

Compound Nouns

A compound noun is made up of a noun plus another noun. Take moonlight as an example. However, compound nouns are also made using other parts of speech, like verbs and adjectives.

Think of the word haircut. Hair on its own is a noun. Cut is often used as a verb, but when you put those two words together, it becomes a noun again. Please note that the order of a compound noun is not limited to noun + noun, or noun + other parts of speech. Many combinations can produce a compound noun. For example, a verb + a noun can also create a compound noun (e.g., swimsuit).

There are opened, closed, and hyphenated compound nouns. Below are a few examples of each.

Often, many words start as open compound words, and eventually turn into closed compound words (e.g., notebook). There are a few standards that can be remembered to know whether a compound word should be opened, closed, or hyphenated. For example, a noun + noun compound word is usually closed (e.g., boyfriend). A compound word that uses a verb + “ing” is often written as an open compound (e.g., dry cleaning).

Compound Adjectives

Compound adjectives are two words joined into one to describe a noun (or compound noun). Like compound nouns, they can contain different parts of speech. Compound adjectives are mostly written with hyphens, but there are also opened and closed forms of these words.

Here are a few examples of compound adjectives:

• Noun + noun + adjective:

Last time she walked by the lake, she saw a seven-foot-long alligator.

• Adjective + noun:

They were in a long-distance relationship for seven years.

• Adverb + past participle:

A new school had to be built because the old one was overpopulated.

Compound Verbs

There are several types of compound verbs, like phrasal verbs, prepositional verbs, and helping verbs. Here, we are only going to focus on single-word compound verbs. Like in compound nouns and adjectives, these verbs are made by joining two words. Below are a few examples of compound verbs:

I was looking for someone who could babysit my kids for the weekend.

He was notorious for overcooking steaks.

For her birthday, she wanted to test-drive a new Ferrari.

I didn’t want to overstay my visit.

He had to sound-proof his apartment.

Keep in mind that compound verbs are usually written with a hyphen or as a closed compound.