Meaning compound words

Compound Words: Everything You Need to Know

The words pancake, living room, and merry-go-round have something in common.

They are all examples of compound words.

The noun compound means something made up of two or more separate components. Compound can also be an adjective meaning consisting of two or more parts or components.

A compound word is one word, or one unit of meaning, that is created by joining two or more separate words together.

What Are Compound Words?

A compound word is a word made up of usually two but sometimes more words that are joined together. The two (or more) that make the compound word are independent words; they have their own distinct meanings. When those words are joined and form a compound word, that compound word has its own new meaning.

The Three Types of Compound Words

Compound words can take three possible forms: closed, open, or hyphenated. In closed form, there is no space between the joined words. In open form, there is a space between the “joined” words that still act as one unit, and in hyphenated form—you guessed it! There is a hyphen between the joined words.

These general “rules”—which are somewhat fluid and flexible—provide guidance as to what format a compound word takes.

  • Closed compound words are usually nouns: They put on makeup.

  • Open compound words are usually nouns or verbs: I have to make up (verb) that exam at my high school. (noun)

  • Hyphenated compound words are usually adjectives or adverb-adjective combinations: I have to take a make-up (adjective) exam. I will be well-prepared. (adverb + adjective)

The key word in each of those examples is “usually.” Some compound words break the rules. We'll see how soon.

1. Closed Compound Words

To review: closed compound words are usually made up of two separate words that are put together to form a new word. There is no space between the two words in a closed-form compound word; the compound appears as one single word.

Examples of Closed Compound Words

  • Cup + cake becomes cupcake

  • Basket + ball becomes basketball

  • Key + board becomes keyboard

  • Extra + ordinary becomes extraordinary

  • Birth + day becomes birthday

You can see through these examples that the meaning of the compound word is not just a merger of the independent definitions of the individual words that join together to make that compound.

However, there is a relationship between the individual word meanings and the compounds. Compound words have been integrated into language as speakers have discovered those relationships. It makes perfect sense to call a cake that could fit into a cup a cupcake and to call a ball thrown through a basket (now a hoop) a basketball.

The rules for compound words, listed earlier in the post, include the word usually. That word means the rules are not hard and fast, and there are examples of compound words that break those rules.

For example, compound words that are verbs are usually open form, but here are rule-breaking closed-form compound verbs that remind us to hold those rules loosely:

  • I need to proofread my essay.

  • I think the clerk shortchanged me.

  • I have to babysit my little sister.

2. Open Compound Words

In an open compound word, there is a space between the two independent words, though they are still treated as one unit with a new “compound meaning.”

Examples of Open Compound Words

  • Living room: as a unit, this compound noun refers to a room in a house.

  • High school: as a unit, this compound noun refers to a school that has students in grades 9-12.

  • Post office: as a unit, this compound refers to a building where mail is collected, sorted, and sent.

  • Give up: as a unit, this compound verb means to stop trying.

  • Ask for: as a unit, this compound verb means to request something.

3. Hyphenated Compound Words

Hyphenated compound words have hyphens between each of the independent words that serve as connectors. The hyphens are a visual cue that the words form one unit.

Some compound words are always hyphenated.

Did you notice that all of those examples are nouns? Remember: the rules are flexible!

Examples of Hyphenated Compound Adjectives:

When compound words are used as adjectives (officially known as compound adjectives), the hyphenation rules change depending on where the compound adjective comes in the sentences.

If the compound adjective comes before the noun it modifies (describes), you should usually add a hyphen:

Of course, there are exceptions. Remember, those “rules” are flexible. Some compound adjectives that precede the nouns they modify never take a hyphen. For example, ice cream and high school:

  • High school students
  • Ice cream sundae

There’s really no “why” to explain these exceptions; we’ve just adopted these forms and made them part of our language.

Examples of Open-Form Compound Adjectives

If the compound adjective comes after the noun it modifies, the hyphen is usually omitted.

  • Make sure the files are up to date. “Up to date” modifies, but comes after, the noun “files.”

  • The cat is two years old. “Two years old” modifies, but comes after, the noun “cat.”

Though post-noun modifiers don’t technically take hyphens, according to Merriam-Webster, usage trends indicate the hyphens are often included anyway, if the compounds “continue to function as unit modifiers. ” So there’s that flexibility again.

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What About Adverb Compounds?

It’s easy to find examples of closed, open, and hyphenated adverbs.

As for the closed-form examples, we probably don’t even register them as compound words much of the time.

  • Sometimes

  • Thereafter

  • Somewhere

Open-form adverbs occur when the adverb is the first word in the compound and ends in -ly. You should not hyphenate after an -ly adverb.

  • We made the discovery early on.

  • Her opinion is highly regarded.

  • They entered the dimly lit room.

What to Do If You’re Not Sure Which Form Is Right

While those flexible rules can help you, there may still be times when you feel confused about which compound form to use. Don’t stress too much.

According to Merriam Webster, the rules are more like patterns. You may see differences in different publications depending on editorial choice and style. For example, I looked on Amazon for a teapot. I saw mostly teapots, but also a few tea pots. Out of curiosity I put “tea pot” into a New York Times search bar, and found articles from the 1800s that included “tea-pot” in the title!

While interesting, those stylistic changes and choices shouldn’t be too surprising. Language is fluid and ever-evolving. Compound words themselves are proof of that evolution.

Keep Clarity the Focus

The purpose of hyphens in compound words is to ensure clarity. For example,

In the first example, I know by the hyphen that the medicine "I" bought did not require a prescription. "Over-the-counter" is one unit—one compound—describing a type of medicine.

In the second example, "over the counter" is serving another purpose and, while the words form a phrase to tell me where "he" passed the medicine, hyphens do nothing to make the purpose of the phrase clear and are therefore unnecessary.

Now look at these examples:

  • He owned a little-used car.
  • He owned a little used car.

In the first example, I know the man owns a car that has not been driven much. The car is described by the compound modifier "little-used."

In the second example, it seems that the man owns a used car that is also small, or little. In this example, putting a comma after "little" would help to separate the two words, "little" and "used," and show that they aren't intended to work as a compound.

ProWritingAid Can Help

Though you’re a compound-word expert now, if you find yourself with lingering doubts, remember that ProWritingAid is here to help. It will let you know if you’ve added an unnecessary hyphen after an -ly adverb, or if you’ve left one out of a pre-noun compound adjective. You don’t have to write alone!

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Compounds - English Grammar Today

Grammar > Words, sentences and clauses > Word formation > Compounds

A compound word is two or more words linked together to produce a word with a new meaning:

  1. tooth + brush = toothbrush eco + friendly = eco-friendly animal + lover = animal lover

We make compounds in all word classes:

nouns: car park, soap opera

pronouns: anyone, everything, nobody

adjectives: environmentally-friendly, fat-free

numerals: twenty-seven, three-quarters

verbs: daydream, dry-clean

prepositions: into, onto

adverbs: nevertheless, nowadays

conjunctions: although, however

See also:

  • Hyphens

We usually make compound nouns with a noun + noun, with a verb (or a word made from a verb) + noun, or with an adjective + noun:

noun + noun: earphones

verb -ing form + noun: parking ticket

verb base form + noun: rescue team

adjective + noun: blackboard

The usual spoken stress pattern is with stress on the first item (earphones, blackboard).

In a compound noun, we can combine different elements. These include:

  1. subject + verb: earache (an ear that aches), rainfall (rain that falls)

  2. verb + subject: cleaning products (products that clean)

  3. verb + object: know-all (person who thinks they know everything)

  4. object + verb: shoe-polish (polishes shoes), dishwasher (washes dishes)

See also:

  • Hyphens

  • Noun phrases: order

Compound adjectives most commonly end in an adjective (e.g. homesick), or in an -ing or -ed adjective form (e.g. ground-breaking, short-sighted).

Compound verbs are far less common than compound nouns or adjectives. They can be made by making a verb from another word class, normally from an already existing compound noun (e.g. a daydreamto daydream).

Sometimes compound words are written separately (nail polish), sometimes with a hyphen (short-sighted) and sometimes as one word (eyelashes). Often new compounds are written as two separate words and, as they become more familiar, they are either connected with a hyphen (-) or made into one word.

There are some general rules and guidelines for when to use hyphens:

The band has decided to re-form. (form again)

The Government promise to reform the health system. (improve)

A twenty-two-year-old cyclist won the race.

From here to Tokyo, that’s a twelve-hour flight at least.

If you’re not sure about whether to use a hyphen, a good dictionary will tell you.

See also:

  • Hyphens

  • Punctuation

A compound sentence has two or more main clauses linked by coordinating conjunctions, such as and, but:

[main clause 1]She did a nursing degree [main clause 2]and she did really well, [main clause 3]but she’s decided to study medicine now.

See also:

  • Clauses: coordinated


  • 01 Present perfect simple or present perfect continuous?
  • 02 Would rather, would sooner
  • 03 To
  • 04 Suggest
  • 05 As, when or while?
  • 06 Hate, like, love and prefer
  • 07 Past continuous or past simple?
  • 08 As, because or since?
  • 09 Look forward to
  • 10 Present perfect continuous (I have been working)

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