Compound Words

What Are Compound Words?

Compound words are formed by combining two or more individual words to create a new word with its own meaning. The resulting word may look, sound, or be spelled differently from its component parts — but its meaning is distinct and usually easy to recognise in context.

For example, “sun” and “flower” are two separate words, but together they form “sunflower” — a specific plant with its own identity. Similarly, “ice” and “cream” combine to give us “ice cream,” a phrase so familiar that we rarely think of it as two words at all.

Compound words are everywhere in English, and understanding how they work helps you use them correctly — particularly when it comes to knowing whether to write them as one word, with a hyphen, or as two separate words.

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The Three Types of Compound Words

There are three main types of compound words in English. The type determines how the word is written — closed, hyphenated, or open.

1. Closed Compound Words

Closed compounds are written as a single word, with no space or hyphen between the two parts. These are the most common type and are usually formed when two words have been used together so frequently that they have merged into one.

Examples: notebook, football, sunflower, bedroom, toothbrush, backpack, keyboard, skateboard

When in doubt about whether a closed compound should be one word or two, check a reliable dictionary — usage evolves over time and some words transition from open to closed as they become more established.

2. Hyphenated Compound Words

Hyphenated compounds use a hyphen to connect two or more words. The hyphen clarifies the relationship between the words and prevents ambiguity. They are particularly common when a compound modifier comes before a noun.

Examples: mother-in-law, well-being, part-time, self-esteem, state-of-the-art, up-to-date, cost-effective, long-term

Note that hyphenation rules can vary between British and American English, and between style guides. When writing professionally, it is worth checking your organisation’s preferred style guide.

3. Open Compound Words

Open compounds are written as two separate words but function as a single concept. These are often the trickiest to identify because they look like two ordinary words sitting next to each other.

Examples: ice cream, post office, high school, coffee shop, living room, real estate, cell phone, family tree

Open compounds are typically noun phrases that have become so commonly used together that they are recognised as a unit. Over time, many open compounds become closed compounds as usage evolves.

100 Compound Word Examples

Here is a reference list of 100 common compound words in English, organised by type:

Closed Compound Words

Hyphenated Compound Words

Open Compound Words

How to Use Compound Words Correctly

Knowing which form to use — closed, hyphenated, or open — is one of the trickier aspects of English spelling and punctuation. Here are some practical rules to guide you:

• Check a dictionary first. Many compound words have established spellings that vary by context. “Everyday” (adjective) and “every day” (adverb phrase) are a good example — they look similar but mean different things.
• Hyphenate compound modifiers before a noun. When two words act together as an adjective before a noun, use a hyphen: “a well-known author.” But when the same phrase follows the noun, no hyphen is needed: “the author is well known.”
• Be consistent throughout your document. If you write “email” in one place, do not write “e-mail” in another. Pick one form and stick to it.
• Follow your style guide. Different guides (Oxford, Chicago, APA, etc.) have different conventions for hyphenation. Academic and professional documents should follow the appropriate guide for their field.
• Watch out for words that change meaning. “Makeup” (cosmetics) and “make up” (to reconcile) are entirely different. The same applies to “breakdown” vs “break down,” “login” vs “log in,” and many others.

Not sure which form is correct for your document? Our copy editing service checks hyphenation, consistency and word choice throughout your document. Submit your document today.

Compound Words in Professional Writing

Compound words appear constantly in professional and academic writing — often without writers noticing. Getting them right matters because inconsistency or incorrect hyphenation can make a document look careless, even when the underlying content is strong.

Some of the most commonly misused compound words in professional writing include:

At Proofers, our editors check for hyphenation consistency and correct compound word usage as part of every proofreading and copy editing order.

FAQs

What is a compound word?

A compound word is formed when two or more words are combined to create a new word with its own distinct meaning. Compound words can be written as one word (closed), with a hyphen (hyphenated), or as two separate words (open).

What are the three types of compound words?

The three types are closed compounds (written as one word, e.g. “notebook”), hyphenated compounds (joined by a hyphen, e.g. “well-being”), and open compounds (written as two words, e.g. “ice cream”). Each type follows its own conventions depending on usage and style guide.

How do I know whether to hyphenate a compound word?

As a general rule, hyphenate compound modifiers that appear before a noun (e.g. “a well-known author”) but not when they follow a noun (e.g. “the author is well known”). When in doubt, check a dictionary or your relevant style guide — Oxford, Chicago and APA all have slightly different conventions.

Can compound words change meaning depending on how they are written?

Yes — and this is one of the most common sources of error in professional writing. “Make up” (verb: to reconcile), “make-up” (adjective: a make-up test) and “makeup” (noun: cosmetics) all mean different things. The same applies to “breakdown” vs “break down,” “login” vs “log in,” and “follow-up” vs “follow up.”

Will a proofreader check my use of compound words?

Yes — our professional proofreading service checks for spelling, hyphenation and consistency throughout your document, including correct use of compound words. All orders are returned within 24 hours with a full money-back guarantee.

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