How Do You Know When To Put A Hyphen Between Compound Words?

Emily Thomas

Have you ever wondered when to use a hyphen between compound words? It’s a common question that many people struggle with. In this article, we will explore the rules and guidelines for using hyphens in compound words, providing you with the knowledge and confidence to use them correctly.

Understanding Compound Words

Definition of compound words

Compound words are formed when two or more words are combined to create a new word with a different meaning. These words can be comprised of two nouns, an adjective and a noun, a verb and a noun, or any other combination. The meaning of a compound word is often different from the individual words that make it up. For example, the compound word “blackboard” refers to a writing surface, not just a color and a board.

Examples of compound words

Compound words are commonly used in the English language. Some examples include:

  • Butterfly: a type of insect with colorful wings
  • Rainbow: a multicolored arc in the sky, formed by the reflection, refraction, and dispersion of light
  • Basketball: a sport played with a round ball and two teams of five players
  • Traffic jam: a situation where a large number of vehicles are congested on a road, causing a delay in movement
  • Mother-in-law: the mother of one’s spouse

Compound words are versatile, allowing us to convey complex ideas in a single word. Understanding the different types of compound words and how to properly incorporate hyphens is essential for clear and effective communication.

Determining the Need for a Hyphen

General Guidelines

Determining whether a hyphen is needed in a compound word can be challenging. However, there are some general guidelines that can help make this decision clearer.

The first guideline is to consider the purpose of the hyphen. Hyphens are used to connect the different components of a compound word and signal that they function together as a single unit. Additionally, hyphens are used to eliminate ambiguity and improve readability.

Another important guideline is to consider the established norms and style guides. There are certain compound words that are widely accepted to be written as one word, while others may require a hyphen. Consulting reputable dictionaries and style guides can provide valuable guidance in determining the appropriate usage.

Compounds with Prefixes and Suffixes

In compound words with prefixes and suffixes, the need for a hyphen largely depends on whether the resulting word is clear and unambiguous without it. If the meaning of the word could be misunderstood without a hyphen, it is advisable to use one.

For example:

  • Re-cover: If you say “recover,” it could be misinterpreted as meaning “to regain consciousness,” whereas “re-cover” clearly means “to place a new cover on something.”
  • Co-worker: “Coworker” indicates someone who works with cows, while “co-worker” refers to a colleague you work with.

By incorporating a hyphen, you can eliminate any confusion and ensure that your intended meaning is conveyed accurately.

Compounds with Numerals or Letters

When working with compound words that include numerals or letters, the general rule is to use a hyphen. This is especially important when the compound word expresses a range or sequence, such as “pre-2020” or “A-level.”

Using a hyphen in these instances helps to clarify that the numerals or letters are an integral part of the compound word and not separate entities.

How Do You Know When To Put A Hyphen Between Compound Words?

General Rules for Hyphenating Compound Words

Using a Hyphen in Compound Adjectives

Compound adjectives are formed when two or more adjectives are combined to describe a noun. In these cases, a hyphen is typically used to connect the adjectives and create cohesion.

For example:

  • Well-written essay: The hyphen in “well-written” shows that the essay is written in a skillful and proficient manner.
  • Heavy-duty equipment: The hyphen in “heavy-duty” indicates that the equipment is designed to withstand heavy and demanding use.

Using hyphens in compound adjectives prevents confusion and ensures that the intended meaning is clear.

Using a Hyphen in Compound Nouns

When two nouns are combined to create a new noun with a specific meaning, a hyphen is commonly used to connect them.

For example:

  • Ice-cream: It refers to a frozen dessert made from dairy products and flavorings.
  • Raincoat: A coat designed to protect the wearer from rain.

Hyphenating compound nouns helps to distinguish them from separate words and signals that they function as a single unit.

Using a Hyphen in Compound Verbs

Compound verbs are created by combining a verb with another word, usually a noun or an adjective. These verbs often require a hyphen to provide clarity and indicate that they form a single concept.

For example:

  • Bounce back: To recover quickly from a setback or difficulty.
  • Cut off: To completely separate or disconnect something.

Using hyphens in compound verbs ensures that the intended action is expressed unambiguously and simplifies comprehension.

Compounds with Prefixes and Suffixes

Hyphenating Prefixes

When a prefix is added to a word to create a compound word, the need for a hyphen depends on the specific prefix and the resulting word. It is important to consult dictionaries or style guides to determine the appropriate usage.

In general, common prefixes such as “re-,” “pre-,” and “un-” typically require a hyphen. This helps to clarify the meaning of the word and avoid confusion.

For example:

  • Re-enter: The hyphen in “re-enter” indicates that the person is entering again after a previous exit.
  • Pre-approved: The hyphen in “pre-approved” distinguishes it from “preapproved,” which could be misinterpreted as “before being approved.”

Hyphenating Suffixes

Similar to prefixes, the decision to use a hyphen with suffixes depends on the suffix and the clarity of the resulting word. Some suffixes, like “-like” or “-free,” often require a hyphen for readability.

For example:

  • Child-like: The hyphen in “child-like” clarifies that the behavior or qualities resemble those of a child.
  • Gluten-free: The hyphen in “gluten-free” indicates that the product does not contain gluten.

Again, consulting dictionaries and style guides can provide specific guidance on hyphenation with different suffixes.

How Do You Know When To Put A Hyphen Between Compound Words?

Hyphenation in Numerals or Letters

Hyphenating Numerals

When compound words include numerals, using a hyphen is generally recommended. This is especially crucial when the numerals express a range or sequence.

For example:

  • 21-30: This range of numbers is commonly written with a hyphen to clarify that it includes all values between 21 and 30.
  • 5th-grade: The hyphen in “5th-grade” highlights that it refers to the grade level, rather than an ordinal number followed by “grade.”

Hyphenating numerals in compound words ensures accuracy and avoids confusion about the intended meaning.

Hyphenating Letters

When compound words include letters, such as acronyms or abbreviations, using a hyphen can help enhance clarity and readability.

For example:

  • A-level: The hyphen in “A-level” indicates that it refers to a specific type of educational qualification.
  • e-mail: The hyphen in “e-mail” shows that it is an abbreviation for electronic mail.

By incorporating hyphens in compound words with letters, you can prevent any potential misinterpretation and ensure effective communication.

Exceptions to the Rule

Commonly Used Compound Words without Hyphens

While hyphens are commonly used in compound words, there are exceptions where certain compound words are written as one word without a hyphen. These exceptions are typically words that have become widely accepted as a single unit over time.

Examples of compound words commonly written without hyphens include “bedroom,” “football,” “sunflower,” and “baseball.” These words have become so ingrained in the English language that they are now considered standalone words rather than combinations of multiple words.

Compound Words with Changing Meanings

Some compound words undergo changes in meaning when a hyphen is added or removed. These changes can be subtle but impactful.

For example:

  • Hardcover vs. Hard cover: “Hardcover” refers to a book with a sturdy cover, while “hard cover” implies that the cover is difficult to open.
  • Long-term vs. Long term: “Long-term” refers to a duration of extended length, while “long term” could be understood as a combination of a long item and a term.

It is crucial to pay attention to the presence or absence of hyphens in compound words, as they can alter the intended meaning significantly.

Differentiating Between Compound Words and Phrases

Understanding the Difference

It is important to differentiate between compound words and compound phrases to ensure accurate and effective communication. While compound words are formed by combining two or more words to create a new word, compound phrases are made up of separate words that work together to convey a specific meaning.

For example:

  • Compound word: “Drycleaning” refers to a process of cleaning clothes without using water.
  • Compound phrase: “Dry cleaning” refers to the act of cleaning clothes without using water.

Hyphens play a vital role in distinguishing between compound words and compound phrases. Using hyphens in compound words helps to merge the individual words into one cohesive unit, while compound phrases remain separate entities.

Hyphenation in Compound Phrases

Compound phrases that consist of multiple words but do not form a compound word do not require hyphens. However, in situations where a compound phrase is used as an adjective modifying a noun, a hyphen may be necessary to improve clarity and readability.

For example:

  • A well-known author: The hyphen in “well-known” clarifies that the author is widely recognized or famous.
  • A green apple: No hyphen is required here, as “green” simply describes the type or color of the apple.

The decision to use a hyphen in compound phrases largely depends on whether it enhances the understanding of the intended meaning.

Hyphenating Non-Standard Compound Words

Consistency in Written Language

While there are established rules and guidelines for hyphenating compound words, it is essential to maintain consistency within your own writing. Consistency helps to create a professional and polished piece of work and aids in clarity and readability for your readers.

For instance, if you choose to use a hyphen in a compound word, consistently apply the same hyphenation style throughout your writing. On the other hand, if you decide not to use a hyphen, ensure that you follow this style consistently as well.

By maintaining consistency, you establish a clear and coherent writing style that helps your readers understand your intended meanings more easily.

Consulting Style Guides

To further assist in determining the correct hyphenation style, it is advisable to consult relevant style guides. Style guides provide detailed guidelines and recommendations on grammar, punctuation, and usage.

Depending on your field or industry, there may be specific style guides that are widely recognized and followed. For instance, the Associated Press (AP) Stylebook is commonly used in journalistic writing, while the Chicago Manual of Style is popular in academic and publishing settings.

By referring to appropriate style guides, you can ensure that your writing adheres to established standards and effectively communicates your message.

Utilizing Dictionaries and Online Resources

Understanding Dictionary Usage

Dictionaries are valuable tools in determining the correct hyphenation of compound words. They provide the official definitions, spellings, and usages of words, including whether and how they should be hyphenated.

When in doubt, referring to reputable dictionaries, both online and offline, can help clarify the appropriate hyphenation style. Pay close attention to the pronunciation guides and hyphenation indicators provided in the dictionary entries.

Online Tools for Hyphenation

In addition to dictionaries, various online resources and tools are available for hyphenation assistance. Online hyphenation tools allow you to enter a word or a phrase, and they provide hyphenation suggestions based on established rules and usage.

These tools can be especially useful when working with complex compound words or phrases that require multiple hyphenations. However, it is important to cross-reference the results from online tools with established dictionaries and style guides to ensure accuracy and reliability.


Understanding compound words and knowing when to use hyphens is essential for clear and effective communication. By following the general guidelines, specific rules for hyphenating compound adjectives, nouns, and verbs, and considering prefixes, suffixes, numerals, and letters, you can hyphenate compound words correctly.

Additionally, being aware of exceptions to the hyphenation rules, differentiating between compound words and phrases, maintaining consistency in your writing, and utilizing dictionaries and online resources for guidance will further enhance your proficiency in hyphenation.

By mastering the art of hyphenation, you can ensure that your writing is professional, polished, and easily understood by your readers. So, embrace the power of compound words and hyphens, and take your communication skills to the next level!