Hyphens: Definition, Usage, and Examples

The hyphen, a small but mighty punctuation mark, often causes confusion for English language learners and native speakers alike. Mastering its usage is crucial for clear and precise writing.

A wrongly placed or omitted hyphen can alter the meaning of a sentence, leading to misinterpretation. This article aims to provide a comprehensive guide to understanding hyphens, covering their definition, different types, usage rules, common mistakes, and advanced applications.

Whether you’re a student, a professional writer, or simply someone looking to improve their grammar, this guide will equip you with the knowledge and skills to use hyphens correctly and confidently.

Table of Contents

• Definition of a Hyphen
• Structural Breakdown
• Types and Categories of Hyphens
  • Hyphenated Compound Words
  • Suspensive Hyphens
  • Hyphens for Word Breaks
• Examples of Hyphen Usage
  • Compound Adjectives
  • Compound Nouns
  • Prefixes and Suffixes
  • Numbers and Fractions
  • Suspensive Hyphens
• Usage Rules for Hyphens
  • Compound Adjectives Before Nouns
  • Compound Adjectives After Nouns
  • Prefixes and Suffixes
  • Hyphens for Clarity
  • Avoiding Ambiguity
• Common Mistakes with Hyphens
• Practice Exercises
• Advanced Topics
  • The En Dash
  • The Em Dash
  • Hyphenation in Typography and Software
• Frequently Asked Questions
• Conclusion

Definition of a Hyphen

A hyphen (-) is a punctuation mark that connects two or more words together, indicating that they should be understood as a single unit. It is shorter than both the en dash (–) and the em dash (—).

The primary function of a hyphen is to create compound words, modify nouns with compound adjectives, or divide words at the end of a line. Understanding the nuances of hyphen usage is essential for maintaining clarity and precision in writing.

The hyphen is not merely a stylistic choice; it often plays a crucial role in conveying the intended meaning of a sentence. Consider the difference between “a small business owner” and “a small-business owner.” The former implies an owner who is physically small, while the latter indicates an owner of a small business.

This subtle difference highlights the importance of correct hyphen usage.

Structural Breakdown

The hyphen’s structure is simple: a short, horizontal line. Its function, however, is multifaceted.

Structurally, it serves as a bridge between words, creating a single, unified term. It’s important to distinguish the hyphen from other similar punctuation marks like the en dash and em dash, which have different lengths and usages.

The hyphen is used within words or between words that function together as a single unit. It can join two nouns, an adjective and a noun, or even a prefix and a word.

The key is that the combined elements act as one descriptive element or a single concept. Therefore, the hyphen essentially alters the grammatical role of the words it connects, transforming them into a cohesive whole.

Types and Categories of Hyphens

Hyphenated Compound Words

Compound words are formed when two or more words are joined together to create a new word with a distinct meaning. These can be open (separate words), closed (one word), or hyphenated.

Hyphenated compound words are common, especially when the compound is relatively new or when it serves as an adjective before a noun. Over time, some hyphenated compounds become closed compounds (e.g., email, originally e-mail).

The decision to hyphenate often depends on style guides and common usage, and it can evolve over time. For example, “state-of-the-art” is a hyphenated compound adjective that describes something as being the most current or advanced.

Suspensive Hyphens

Suspensive hyphens, also known as hanging hyphens, are used when a writer lists a series of compound words that share a common base word. Instead of repeating the base word each time, the writer uses a hyphen after the modifying element, leaving the base word to be understood at the end of the series.

This technique saves space and avoids redundancy, making the writing more concise and elegant. For example, instead of writing “first-class and second-class tickets,” you can write “first- and second-class tickets.” The hyphen after “first” indicates that it modifies the same noun as “second.”

Hyphens for Word Breaks

When a word is too long to fit at the end of a line, it can be broken and continued on the next line using a hyphen. This is particularly common in printed materials where justified text is used.

The hyphen indicates that the word is not complete and that the reader should continue reading it on the next line. Word division should generally occur between syllables to maintain readability.

Many word processing programs automatically handle word breaks, but it’s important to understand the rules for manual hyphenation when necessary. Dictionaries often indicate the correct syllable divisions for words, which can be helpful when manually hyphenating.

Examples of Hyphen Usage

Compound Adjectives

Compound adjectives are formed when two or more words are combined to modify a noun. They are typically hyphenated when they appear before the noun they modify.

The hyphen clarifies that the words function together as a single adjective, preventing misreading. However, when the same compound adjective follows the noun, the hyphen is often omitted.

Below is a table with examples of compound adjectives.

Compound Adjective (Before Noun)	Example Sentence	Un-hyphenated (After Noun)	Example Sentence
Well-known author	She is a well-known author.	Well known	The author is well known.
State-of-the-art technology	The company uses state-of-the-art technology.	State of the art	Their technology is state of the art.
Long-term investment	This is a long-term investment.	Long term	The investment is long term.
High-quality product	They sell high-quality products.	High quality	Their products are high quality.
Part-time job	I have a part-time job.	Part time	My job is part time.
Short-term solution	This is only a short-term solution.	Short term	The solution is only short term.
User-friendly interface	The software has a user-friendly interface.	User friendly	The interface is very user friendly.
Cost-effective method	This is a cost-effective method.	Cost effective	The method is cost effective.
World-renowned chef	He is a world-renowned chef.	World renowned	The chef is world renowned.
Open-minded attitude	She has an open-minded attitude.	Open minded	Her attitude is very open minded.
Fast-paced environment	Working here is a fast-paced environment.	Fast paced	The environment is very fast paced.
Hard-working employee	He is a hard-working employee.	Hard working	The employee is hard working.
Well-behaved children	They are well-behaved children.	Well behaved	The children are well behaved.
English-speaking country	Canada is an English-speaking country.	English speaking	Canada is an English speaking country.
Record-breaking performance	The athlete delivered a record-breaking performance.	Record breaking	The performance was record breaking.
Decision-making process	The company uses a complex decision-making process.	Decision making	The process of choosing is decision making.
Problem-solving skills	She has excellent problem-solving skills.	Problem solving	Her skills are problem solving.
Forward-thinking company	That is a forward-thinking company.	Forward thinking	The company is very forward thinking.
Highly-rated movie	That is a highly-rated movie.	Highly rated	The movie is highly rated.
Full-time student	I am a full-time student.	Full time	I study full time.
Left-handed person	He is a left-handed person.	Left handed	He writes left handed.
Right-handed person	She is a right-handed person.	Right handed	She writes right handed.
Good-looking man	He is a good-looking man.	Good looking	He is good looking.
Old-fashioned dress	She wore an old-fashioned dress.	Old fashioned	Her dress was old fashioned.
Self-made millionaire	He is a self-made millionaire.	Self made	He is self made.
Strong-willed child	She is a strong-willed child.	Strong willed	She is strong willed.
Kind-hearted person	He is a kind-hearted person.	Kind hearted	He is kind hearted.

Compound Nouns

Compound nouns can be written as one word (e.g., sunrise), two words (e.g., living room), or with a hyphen (e.g., mother-in-law). The choice often depends on convention and usage.

It’s best to consult a dictionary when in doubt. Some compound nouns start as two words, then become hyphenated, and eventually become one word as they gain acceptance in common usage.

Consider “e-mail” which has largely transitioned to “email.” Here are some examples of hyphenated compound nouns.

Hyphenated Compound Noun	Example Sentence
Mother-in-law	My mother-in-law is visiting next week.
Father-in-law	His father-in-law is a retired teacher.
Brother-in-law	Her brother-in-law is a lawyer.
Sister-in-law	My sister-in-law is a doctor.
Self-esteem	Building self-esteem is important for children.
Ex-wife	His ex-wife still lives in the same town.
Ex-husband	Her ex-husband remarried last year.
Editor-in-chief	She is the editor-in-chief of the magazine.
Passer-by	A passer-by saw the accident and called the police.
Check-in	The check-in process was quick and easy.
Check-out	The check-out time is at noon.
Merry-go-round	The children enjoyed riding the merry-go-round.
T-shirt	He wore a plain white T-shirt.
Dry-cleaning	I need to take my suit to the dry-cleaning.
Up-to-date	The information needs to be up-to-date.
Well-being	Her well-being is her top priority.
Co-worker	He is my co-worker in the office.
Vice-president	She is the vice-president of the company.
Son-in-law	Their son-in-law is a vet.
Daughter-in-law	Her daughter-in-law is a teacher.
Know-how	He has the know-how to fix it.
Off-season	The hotel offers lower rates in the off-season.
One-off	It was a one-off event.
Hand-me-down	The clothes were a hand-me-down.
Make-up	She wore make-up for the party.
Step-brother	He is my step-brother.
Step-sister	She is my step-sister.

Prefixes and Suffixes

Hyphens are sometimes used with prefixes and suffixes, especially when adding a prefix to a proper noun or when the prefix ends with the same letter that the root word begins with. However, many prefixes and suffixes are simply attached to the root word without a hyphen. Common prefixes that sometimes take a hyphen include self-, ex-, and co-. The rules can be complex and vary depending on the specific prefix and the word it’s attached to. Consulting a dictionary or style guide is always a good practice.

Prefix/Suffix + Word	Example Sentence
Self-aware	He is a very self-aware individual.
Ex-president	The ex-president gave a speech.
Co-worker	She is my co-worker in the marketing department.
Re-enter	Please re-enter your password.
Pre-existing	The contract covers pre-existing conditions.
Anti-inflammatory	This medicine is an anti-inflammatory.
De-emphasize	The report seeks to de-emphasize the negative aspects.
Non-essential	These items are considered non-essential.
Semi-independent	The country is now semi-independent.
Un-American	His actions were deemed un-American.
Post-war	The post-war economy was difficult.
Pre-owned	They sell pre-owned vehicles.
Pro-choice	She is a pro-choice advocate.
Counter-intuitive	The solution seemed counter-intuitive at first.
Meta-analysis	The study involved a meta-analysis of previous research.
Re-evaluate	We need to re-evaluate our strategy.
Co-author	He is the co-author of the book.
Co-exist	Different cultures can co-exist peacefully.
Multi-faceted	The issue is multi-faceted.
Sub-Saharan	They are studying Sub-Saharan Africa.
Self-service	This is a self-service gas station.
Ex-boyfriend	He is my ex-boyfriend.
Re-apply	You must re-apply for the job.
Self-taught	He is a self-taught musician.

Numbers and Fractions

Hyphens are used in compound numbers from twenty-one to ninety-nine (e.g., forty-two, eighty-seven). They are also used to write out fractions when they function as adjectives (e.g., a two-thirds majority).

However, when fractions are used as nouns, they are generally not hyphenated (e.g., one half of the pie). The use of hyphens in numbers and fractions helps to avoid confusion and ensures clarity.

Numbers/Fractions	Example Sentence
Twenty-one	There are twenty-one students in the class.
Thirty-two	She is thirty-two years old.
Forty-five	The meeting lasted forty-five minutes.
Sixty-eight	The temperature reached sixty-eight degrees.
Ninety-nine	He scored ninety-nine points in the game.
One-half	He ate one-half of the pizza.
Two-thirds	Two-thirds of the students passed the exam.
Three-quarters	He completed three-quarters of the project.
One-fifth	One-fifth of the population is affected.
Five-sixths	They used five-sixths of the material.
Twenty-first	This is the twenty-first century.
Thirty-second	He finished in thirty-second place.
Forty-fifth	It was their forty-fifth anniversary.
Sixty-eighth	This is the sixty-eighth edition.
Eighty-second	He is in his eighty-second year.
One-hundredth	This is the one-hundredth time I’ve told you.
Three-hundred	It costs three-hundred dollars.
One-thousand	There are one-thousand people attending.
One-million	It costs one-million dollars.
Two-billion	The project costs two-billion dollars.
Twenty-two	She is twenty-two years old.
Thirty-three	The number of people is thirty-three.
Forty-four	The number of people is forty-four.
Fifty-five	The number of people is fifty-five.
Sixty-six	The number of people is sixty-six.

Suspensive Hyphens

As mentioned earlier, suspensive hyphens are used to avoid repeating a common base word in a series of compound words. This creates a more concise and readable sentence.

The hyphen “suspends” the base word until the end of the series, where it is understood to apply to all the preceding elements.

Suspensive Hyphen Example	Full Sentence Equivalent
First- and second-class tickets	First-class tickets and second-class tickets
Short- and long-term goals	Short-term goals and long-term goals
Pre- and post-operative care	Pre-operative care and post-operative care
Elementary- and middle-school students	Elementary-school students and middle-school students
Part- and full-time employees	Part-time employees and full-time employees
Two- and three-year warranties	Two-year warranties and three-year warranties
Five- and six-course meals	Five-course meals and six-course meals
Eight- and ten-page papers	Eight-page papers and ten-page papers
Blue- and green-colored pencils	Blue-colored pencils and green-colored pencils
One- and two-bedroom apartments	One-bedroom apartments and two-bedroom apartments
Small- and medium-sized businesses	Small-sized businesses and medium-sized businesses
High- and low-income families	High-income families and low-income families
North- and south-facing windows	North-facing windows and south-facing windows
East- and west-coast offices	East-coast offices and west-coast offices
Men’s- and women’s-clothing dept.	Men’s clothing department and women’s clothing department
Under- and over-the-counter drugs	Under-the-counter drugs and over-the-counter drugs
Pre- and post-natal care	Pre-natal care and post-natal care
Black- and white-footed albatross	Black-footed albatross and white-footed albatross
Four- and five-star hotels	Four-star hotels and five-star hotels
First- and last-born children	First-born children and last-born children
Pre- and elementary school	Pre-school and Elementary school
Mid- and late-season crops	Mid-season crops and late-season crops

Usage Rules for Hyphens

Compound Adjectives Before Nouns

The most common rule for hyphen usage involves compound adjectives that precede the noun they modify. When two or more words function together as a single adjective before a noun, they should be hyphenated.

This helps to avoid ambiguity and ensures that the reader understands the relationship between the words. For instance, “a blue-green sea” is clearer than “a blue green sea,” as it indicates that “blue-green” is a single adjective describing the sea.

Compound Adjectives After Nouns

When a compound adjective follows the noun it modifies, the hyphen is generally omitted. This is because the relationship between the words is usually clear from the context.

For example, “The sea was blue green” does not require a hyphen because the meaning is unambiguous. However, there are exceptions to this rule, particularly when the compound adjective is a well-established phrase or when omitting the hyphen would create confusion.

Prefixes and Suffixes

The rules for hyphenating prefixes and suffixes are less rigid and often depend on style preferences and specific word combinations. As a general guideline, use a hyphen when adding a prefix to a proper noun (e.g., anti-American) or when the prefix ends with the same letter that the root word begins with (e.g., re-enter). Also, use a hyphen with prefixes like self-, ex-, and co- in certain cases. However, many common prefixes and suffixes are simply attached to the root word without a hyphen (e.g., preheat, undo, helpful). Always consult a dictionary or style guide when in doubt.

Hyphens for Clarity

In some cases, hyphens are used to enhance clarity, even if the standard rules don’t strictly require them. This is particularly important when omitting a hyphen could lead to misinterpretation or ambiguity.

For example, consider the phrase “small business owner.” Without a hyphen, it could be interpreted as an owner who is physically small. Adding a hyphen, “small-business owner,” clarifies that it refers to an owner of a small business.

Avoiding Ambiguity

The primary goal of using hyphens is to avoid ambiguity and ensure that the intended meaning of a sentence is clear. When faced with a situation where the absence of a hyphen could lead to confusion, it’s generally best to use one.

This is especially true in technical or specialized writing where precision is paramount. Always consider the potential for misinterpretation and use hyphens strategically to guide the reader’s understanding.

Common Mistakes with Hyphens

One common mistake is omitting hyphens in compound adjectives before nouns, leading to ambiguity. For example, writing “high school students” instead of “high-school students” can be confusing.

Another frequent error is using hyphens unnecessarily, such as in phrases where the meaning is clear without them. It’s also important to distinguish between hyphens, en dashes, and em dashes, as they have distinct uses.

Using the wrong type of dash can alter the tone and meaning of a sentence.

Incorrect	Correct	Explanation
High school students	High-school students	Compound adjective before noun
The project was long term.	The project was long-term.	Compound adjective modifying the noun.
A well known actor	A well-known actor	Compound adjective before noun
The interface was user friendly.	The interface was user-friendly.	Compound adjective modifying the noun.
Re enter the data.	Re-enter the data.	Prefix ‘re-‘ followed by a word starting with ‘e’
Self esteem is important.	Self-esteem is important.	Compound Noun
The ex wife visited.	The ex-wife visited.	Compound Noun
A two thirds majority	A two-thirds majority	Fraction used as an adjective
The color was blue green.	The color was blue-green.	Compound adjective modifying the noun.
A small business owner	A small-business owner	To avoid misinterpretation

Practice Exercises

Test your knowledge of hyphen usage with these practice exercises. Determine whether a hyphen is needed in each sentence and insert one where appropriate.

If the sentence is already correct, mark it as “Correct.” These exercises cover various hyphenation rules, including compound adjectives, prefixes, and suspensive hyphens.

Question	Answer
1. She is a world renowned scientist.	1. She is a world-renowned scientist.
2. The company uses state of the art technology.	2. The company uses state-of-the-art technology.
3. He is a hard working employee.	3. He is a hard-working employee.
4. They offer pre and post natal care.	4. They offer pre- and post-natal care.
5. The children are well behaved.	5. The children are well-behaved.
6. He is a self made millionaire.	6. He is a self-made millionaire.
7. The book is up to date.	7. The book is up-to-date.
8. They sell high quality products.	8. They sell high-quality products.
9. I have a part time job.	9. I have a part-time job.
10. Correct	10. She is thirty-two years old.
11. He is an open minded person.	11. He is an open-minded person.
12. Correct	12. My mother-in-law is visiting.
13. The color is blue green.	13. The color is blue-green.
14. The project is long term.	14. The project is long-term.
15	15. She is a kind hearted person.	15. She is a kind-hearted person.

Advanced Topics

The En Dash

The en dash (–) is longer than a hyphen but shorter than an em dash. It is primarily used to indicate a range of values (e.g., 2010–2020) or to connect related words in a compound adjective when one of the words is already a compound (e.g., post–World War II era).

The en dash adds a level of nuance and precision that the hyphen cannot provide.

The Em Dash

The em dash (—) is the longest of the dashes and is used to set off parenthetical information or to indicate a sudden break in thought. It can replace commas, parentheses, or colons, depending on the desired effect.

The em dash is more emphatic than a comma and less formal than parentheses, providing a versatile tool for adding emphasis and clarity to writing.

Hyphenation in Typography and Software

Modern word processing software and typography tools often include automatic hyphenation features that intelligently break words at the end of lines. These tools use algorithms and dictionaries to ensure that words are divided correctly, following established hyphenation rules.

While these features can be helpful, it’s important to review the results to ensure accuracy and to make manual adjustments when necessary. Understanding the underlying principles of hyphenation is crucial for effectively using and troubleshooting these tools.

Frequently Asked Questions

Conclusion

Mastering the use of hyphens is an essential skill for clear and effective writing. By understanding the different types of hyphens, their usage rules, and common mistakes to avoid, you can significantly improve the precision and clarity of your writing.

While the rules may seem complex at first, consistent practice and attention to detail will help you develop a strong command of hyphen usage. Remember to consult dictionaries and style guides when in doubt, and always prioritize clarity and avoiding ambiguity in your writing.