Types of Compound Words (Closed, Open, Hyphenated)

Compound words are formed when two or more words work together to create a new meaning. Depending on how the words are written, compound words are generally divided into three main types: closed, open, and hyphenated compound words.

A closed compound word is written as one word, such as toothbrush or sunflower. An open compound word is written as separate words, such as high school or ice cream. A hyphenated compound word uses a hyphen between the words, such as mother-in-law or well-known.

In this guide, you will learn the three types of compound words, how each type is formed, how to recognize the differences between them, and how to use them correctly with clear examples.

What Are the Three Types of Compound Words?

Compound words are classified into three main types based on how their individual words are written together:

1. Closed compound words – The words are joined together without a space or hyphen.
   Examples: bedroom, football, notebook, toothpaste
2. Open compound words – The words remain separate but work together as a single unit of meaning.
   Examples: ice cream, post office, high school, living room
3. Hyphenated compound words – The words are connected with one or more hyphens.
   Examples: mother-in-law, well-known, part-time, check-in

The main difference between these three types is their written form. Closed compounds are written as one word, open compounds contain spaces, and hyphenated compounds use hyphens.

However, the spelling of compound words is not always predictable. Some compounds may also change from an open or hyphenated form to a closed form as their usage becomes established over time.

Let’s look at each type in more detail.

Closed Compound Words

A closed compound word is formed when two words are joined together and written as one word without a space or hyphen. The combined word has its own meaning and functions as a single word.

For example:

• tooth + brush → toothbrush
• sun + flower → sunflower
• bed + room → bedroom
• note + book → notebook
• rain + coat → raincoat

Common Examples of Closed Compound Words

Here are some commonly used closed compound words:

Closed Compound Words in Sentences

Notice how each closed compound functions as a single word:

• I left my notebook in the classroom.
• The children are playing football outside.
• She bought a new toothbrush.
• We spent the weekend at home.
• The sunflower grew quickly in the garden.

Although closed compounds are written as one word, you cannot always determine whether a compound should be closed simply by joining two words. Compound spellings become established through standard usage, so checking a reliable dictionary is helpful when you are unsure.

Next, let’s look at compound words that are written as two or more separate words.

Open Compound Words

An open compound word is made up of two or more words that are written separately with spaces between them but work together as a single unit of meaning.

For example:

• ice + cream → ice cream

• post + office → post office

• high + school → high school

• living + room → living room

• real + estate → real estate

Although the words remain separate in writing, their combined meaning represents one concept. For example, living room refers to a particular room in a home, while post office refers to a particular type of place.

Common Examples of Open Compound Words

Open Compound Words in Sentences

Here are some examples of open compounds used naturally in sentences:

• We stopped at the post office this morning.

• The children are playing near the swimming pool.

• She works at a local coffee shop.

• Turn left at the next traffic light.

• They bought some ice cream after dinner.

How to Recognize an Open Compound Word

Two words appearing next to each other do not automatically form an open compound. In an open compound, the words regularly work together to express an established concept.

For example, coffee shop refers to a recognized type of business, while a phrase such as hot coffee simply describes coffee that is hot.

Because compound spelling can vary, it is best to check a reliable dictionary when you are unsure whether a compound should be written as one word, two words, or with a hyphen.

Hyphenated Compound Words

A hyphenated compound word is made up of two or more words connected by a hyphen (-). The hyphen shows that the words are closely related and work together as a single unit.

For example:

• mother-in-law

• well-known

• part-time

• check-in

• editor-in-chief

Unlike closed compounds, the individual words remain visible. Unlike open compounds, they are connected by one or more hyphens.

Common Examples of Hyphenated Compound Words

Hyphenated Compound Adjectives

Hyphens are especially common in compound adjectives that appear before a noun.

For example:

• a well-known writer

• a five-year-old child

• a full-time employee

• a high-quality product

• a last-minute decision

The hyphen helps readers understand that the words work together to describe the noun.

However, not every compound adjective is always hyphenated. Its spelling can depend on its position in a sentence, established usage, and dictionary conventions.

For example:

• She is a well-known writer.

• The writer is well known.

Therefore, hyphens should not be added to compound words automatically. When you are uncertain about an established compound, check a reliable dictionary for its standard spelling.

Closed vs Open vs Hyphenated Compound Words

The easiest way to distinguish the three types of compound words is to look at how they are written. All three combine words to express a particular meaning, but their spelling is different.

Key Differences

Closed compound words have no spaces or hyphens between their parts.

• note + book → notebook

• bed + room → bedroom

Open compound words contain a space between the words, but the words work together as one established expression.

• ice + cream → ice cream

• post + office → post office

Hyphenated compound words use one or more hyphens to connect their parts.

• mother-in-law

• part-time

• well-known

The difference is mainly in spelling and written form, not simply in meaning. For example, bedroom, living room, and mother-in-law are all compounds even though one is closed, one is open, and one is hyphenated.

There is no single rule that can predict the spelling of every compound word. Standard forms develop through common usage and may change over time. When you are unsure, checking the word in a current dictionary is the safest approach.

Examples of the Three Types of Compound Words in Sentences

Understanding compound words becomes easier when you see how they are used in everyday English. The following table compares closed, open, and hyphenated compound words through practical sentence examples.

What Do These Examples Show?

The examples demonstrate three important spelling patterns:

• Closed compounds combine words without spaces or hyphens.

• Open compounds contain separate words that function together as an established expression.

• Hyphenated compounds connect their parts using one or more hyphens.

Although their written forms differ, all three types help express specific ideas clearly in English.

For more practice, explore our guide to Compound Words in Sentences, which includes additional examples and exercises.

Conclusion

Compound words are commonly divided into three types: closed, open, and hyphenated compound words. Understanding these types helps you recognize how compound words are written and use them more accurately in English.

A closed compound is written as one word, such as toothbrush. An open compound contains separate words, such as ice cream. A hyphenated compound connects its parts with a hyphen, such as mother-in-law.

Remember that compound spelling is not always predictable and may change over time. When you are unsure about the correct form, check a current dictionary rather than relying only on general rules.

Once you become familiar with these three patterns, identifying and using compound words in everyday English becomes much easier.

• Compound Words in English: Definition, Types & Examples
• Rules for Forming Compound Words
• Common Compound Words in English 
• 200+ Compound Words List
• Compound Words in Sentences
• Word Formation in English