What Is a Hyphen (-)? | Meaning & When to Use
A hyphen (-) is a punctuation mark that is used to connect words (or parts of words) that function together in a sentence or phrase (e.g., “old-fashioned,” “10-year-old,” “break-in”).
Hyphens are often used in compound adjectives, compound nouns, number phrases, and words with prefixes. There are many rules that govern their use, and it’s not always easy to know which words require a hyphen. QuillBot’s Grammar Checker can help you ensure you’re using hyphens correctly.
Most seven-year-olds are in second grade.
Call my office on Monday to schedule a follow-up.
She has been teaching since the mid-1990s.
When to use a hyphen
Hyphens are most frequently used in certain types of adjectives and nouns. They reduce ambiguity by helping to show which words are acting together as a unit.
[Without the hyphen, “break in” would be interpreted as requiring an object of a preposition: a break in what?]
Occasionally, hyphens are also used to help with pronunciation and interpretation of a word (e.g., in the word “pre-eminent,” where the hyphen shows that each “e” is pronounced separately).
You probably have encountered hyphens quite frequently in printed material to show that a word continues on the next line. In this case, a hyphen can appear between essentially any two syllables. However, this does not mean that the word is typically hyphenated.
The types of words that most frequently use hyphenation are:
Compound adjectives
A compound adjective is a group of two or more words that is used as an adjective to describe a noun. Compound adjectives (like all adjectives) can be either attributive (before the noun) or predicative (after the noun, typically following a linking verb).
In general, attributive compound adjectives are hyphenated, while predicative ones are not.
| Attributive | Predicative |
|---|---|
| Colleges are looking for well-adjusted students. | Colleges are looking for students who are well adjusted. |
| An eight-year-old boy is flying his kite. | The boy at the park is eight years old. |
One notable exception to this general rule is compound adjectives formed with adverbs that end in “-ly” (e.g., “highly rated”). Most authorities agree that no hyphen is needed in these cases, essentially because it is already clear that the adverb modifies the word that comes after it. A hyphen would be redundant.
- We’re hoping to have a widely renowned journalist as our guest speaker.
- We’re hoping to have a widely-renowned journalist as our guest speaker.
This does not apply to compound adjectives formed with adverbs that don’t end in “-ly” (e.g., “well-known speaker”).
There is a difference in how British English and American English treat these word combinations.
- American English treats them like other compound adjectives, using a hyphen when the word precedes a noun and no hyphen when the word follows a noun.
- British English typically hyphenates these adjectives in all positions.
| American English | British English |
|---|---|
| The water in the stream was fast flowing. | The water in the stream was fast-flowing. |
| The author is not very well known. | The author is not very well-known. |
Compound nouns
There are three types of compound nouns in English:
- Open compounds, which are written as two separate words (e.g., “ice cream,” “theme park,” “math teacher”)
- Closed compounds, which are written as one word, without hyphens (e.g., “girlfriend,” “bedroom,” “bypass”)
- Hyphenated compounds (e.g., “father-in-law,” “know-it-all,” “follow-up”)
Compounds of more than two words (e.g., “six-year-olds”) are almost always hyphenated. Beyond that, it can be difficult to know how a compound noun should be written. Using a dictionary or a tool like QuillBot’s Grammar Checker is often the best way to figure out how to correctly write compound nouns.
Phrasal verbs used as nouns
Phrasal verbs are two-word phrases made up of a verb plus a particle (usually a preposition word). The phrase acts as a verb that has a different meaning than the verb by itself (e.g., “call” vs. “call off”).
When phrasal verbs are used as verbs, they are not written with a hyphen. However, often, these phrasal verbs are used as nouns with a related meaning. In this case, they are hyphenated (e.g., “a blow-up”) or written as one word (e.g., “a blackout”).
| Phrasal verbs | Used as nouns |
|---|---|
| Do I need to dress up to go to dinner? | The preschool children love to play dress-up. |
| We need to check out of the hotel by noon. | I’ll ask the receptionist about getting a late checkout. |
Prefixes
The overwhelming preference is for words with prefixes to be written without hyphens (e.g., “semicircle,” “rewrite”). However, there are some words with prefixes that do require a hyphen, as explained in the table below.
| Required hyphen situations | Examples |
|---|---|
| When a capitalized word or numeral follows a prefix | anti-American, pre-1990, sub-Saharan |
| With the prefix “self-” | self-conscious, self-serve, self-aware |
| To separate identical vowels or groups of consonants | co-owner, meta-analysis, un-unionized |
| To prevent confusion with a different word | re-cover, re-press (different meanings than “recover,” “repress”) |
Numbers
Typically, two-word numbers under 100 are hyphenated (e.g., “twenty-one,” “fifty-three”). Numbers like “one hundred,” “two thousand,” etc. are not. A number like 153 would thus be written as “one hundred and fifty-three.”
My grandfather lived to be one hundred and two. [no hyphen]
There were two hundred and seventy-five people at the conference.
It’s important to note, though, that many style guides recommend using numerals for numbers 10 and above, so hyphenation is irrelevant.
Fractions are a bit trickier. MLA and Chicago style recommend hyphenating all fractions (e.g., “one-third”).
APA and Oxford, however, recommend hyphenating fractions only when they are used as an adjective before a noun.
| Always hyphenate (MLA and Chicago) | Hyphenate only when adjectives (APA and Oxford) |
|---|---|
| The number of participants increased by one-half. | The number of participants increased by one half. |
| We need a two-thirds majority to pass the rules change. | We need a two-thirds majority to pass the rules change. |
Hyphen vs dash
Hyphens and dashes are often used interchangeably, but dashes have their own specific uses.
There are two types of dashes in English, both of which are longer than a hyphen:
- An en dash (–) is the shorter dash and is used to show number ranges or to report scores. It can also be used in complex compound adjectives (e.g., “New York–style pizza”) or to express a relationship between two entities (e.g., “the U.S.–Mexico border”). Hyphens are sometimes used in place of en dashes in everyday writing because they are easier to type.
The Cowboys defeated the Bears 31–24.
Post–World War II was a time of growth for the U.S. economy.
- An em dash (—) is longer and is used to illustrate a break in a sentence, to show dialogue has been cut off, or to add extra information. Hyphens should never be used in place of em dashes.
The old dog—whose tail never stopped wagging—walked up to the mailman.
Frequently asked questions about hyphens
- What does a hyphen look like?
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A hyphen (-) looks like a very short line. It is shorter than an en dash (–) and an em dash (—). It is also different from an underscore ( _ ).
On a computer keyboard, it is to the right of the zero (0) key. On a phone keypad, it is in the number menu, just underneath the “1” key.
Hyphens are used to connect words or parts of words (e.g., “self-reliant,” “semi-independent”).
- When do you use a hyphen in a sentence?
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Hyphens are used in sentences in many ways. They connect words (or parts of words) that act together as a unit.
Hyphen examples Type of word Example sentence compound adjective He is a well-known actor. compound noun My sister-in-law is an engineer. number There are twenty-five students in my class There are many rules about when hyphens should and should not be used. QuillBot’s Grammar Checker can help you use hyphens correctly in your writing.
- How do you hyphenate a three-word compound adjective?
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In a three-word compound adjective, a hyphen is typically used between each word in the sequence (e.g., “a well-thought-out plan”).
When a three-word compound adjective incorporates a compound proper noun, such as “New York,” it is generally unnecessary to use a hyphen between the words that comprise the proper noun (e.g., “New York-style,” “Great Gatsby-themed,” “Franz Kafka-inspired”).
In cases like these, many writers use an en dash instead of a hyphen (e.g., “New York–style”) to emphasize that both words of the compound noun are connected to the other word to form the compound adjective.
The QuillBot Grammar Checker can help ensure you’re using hyphens correctly.
- Is email hyphenated?
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The word “email” doesn’t have to be hyphenated. Both “email” and “e-mail” are widely used and accepted, although “email” has become more common.
The QuillBot Grammar Checker can help ensure your writing is free of punctuation and spelling errors.
- What’s the difference between an en dash and a hyphen?
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A hyphen (-) is shorter than an en dash and is used to connect words in compound adjectives (e.g., “fast-paced,” “old-fashioned”) or compound nouns (e.g., “seven-year-olds,” “jack-of-all-trades”).
An en dash (–) is slightly longer and can be used for several purposes:
- To indicate number ranges (e.g., “2020–2024”)
- To indicate a relationship or connection (e.g., “the London–Dublin train,” “the employer–employee relationship”)
- To connect complex compound adjectives (e.g., “the Booker Prize–winning novelist”)
In many everyday writing situations, the hyphen is used in place of the en dash because it is easier to type. However, it is important to know the difference for academic and professional writing contexts.
QuillBot’s Grammar Checker can help you ensure you’re using different types of punctuation correctly.
