Hyphens – Definition & Usage

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Hyphens are punctuation marks (-) that can be used to either connect two words together or connect two parts of the same word while separating the syllables.

The use of hyphens within the text is known as hyphenation and can be used in several situations, including when compound modifiers in a sentence come before the word they are modifying.

In this article, we will explore how to correctly make use of the hyphen within academic writing.

Hyphens – In a Nutshell

Hyphenation is used to connect two words together or to connect two parts of the same word. Hyphens are mainly included:

  • when using compound modifiers before a noun
  • when adding certain prefixes or suffixes to words
  • when writing numbers in full
  • when a word at the end of a line has been split in two

Definition: Hyphens

Merriam-Webster’s Dictionary defines hyphens as “a punctuation mark (-) used especially to divide or to compound words, word elements, or numbers”.1

This punctuation mark is commonly used within hyphenated compound words, such as father-in-law, or to provide clarity when using compound modifiers as an adjective before a noun.


  • I stayed at a child-friendly hotel.

In this sentence, the hyphen is used to link the words child and friendly because they serve as a compound modifier for the word hotel.

Without the use of the hyphen in this sentence, it is possible to misinterpret the sentence as referring to a friendly hotel that is also a child.

Hyphens may also be used to show that a single word has been divided into two parts at the end of a line. This usage is commonly seen in books, magazines, and newspapers, and is especially common when a long word ends a line.

Hyphens with compound modifiers

Compound modifiers are two or more words, which adopt the functionality of a single adjective within a sentence.2

This allows the compound modifier to be used to modify a noun. When this occurs, and the compound modifier appears before the noun in a sentence, hyphens should be used.

Examples of using hyphenated compound modifiers:

  • Barry wanted to purchase a high-end computer.

The compound modifier high-end modifies the noun computer.

  • The car has top-of-the-range features.

The compound modifier top-of-the-range modifies the noun features.

If the modifier comes after the noun, a hyphen is not needed. Therefore, it would also be grammatically correct to write the sentence in the following way:

  • The features of the car are top of the range.

Hyphens with participles

When compound modifiers include either a past or present participle, the same rules apply as for other compound modifiers. So, if the compound modifier comes before the noun, it should be hyphenated.

However, it does not need to be hyphenated if the compound modifier comes after the noun.

With this in mind, both of the following examples are correct:

She is a good-looking woman.

He was a self-made millionaire.

An exception to this rule occurs when an adverb ending in “ly” is involved.3 In this case, the compound is not hyphenated, so the following would be correct:

It was an expertly managed situation.

Hyphens and numbers

The relationship between hyphens and numbers is relatively straightforward.

When a number is written out as a full word, any number between twenty-one and ninety-nine should be written with a hyphen.

Larger numbers should be written in the following way:

  • One hundred and ninety-nine

When numbers are written as digits, a hyphen can be used if the number forms the first part of a compound adjective. For instance, you would write:

  • A 30-minute lunch break
  • A 10-second sprint

Hyphens with prefixes

A prefix is a word that is added to an existing word in order to alter the meaning. A number of prefixes are hyphenated, such as ex, all, mid, cross and self.4 This makes the following correct:

The self-service checkout

My ex-girlfriend

An all-inclusive resort

The mid-1990s

Hyphens with suffixes

A suffix is a word added to the end of an existing word, in order to change its meaning. Some suffixes should also be hyphenated:



  • A water-type Pokemon


  • The President-elect

The word like, when used in this way, may also be hyphenated if the preceding word is a proper noun, if the preceding word is three syllables or longer, or if doing so avoids three consecutive appearances of “l”.

With this in mind, the following are all grammatically correct uses of hyphenated suffixes:

A library-like atmosphere

Follows a word with three syllables

A New York City-like metropolis

Follows a proper noun

A shell-like material

Avoids three consecutive “l”


Hyphens are used to join two words together or to connect two parts of the same word. Some words are hyphenated compound words, which should always be written with hyphens, such as father-in-law. However, hyphens can also be used to connect compound modifiers, such as dog-friendly pub or high-quality food.

The symbol for a hyphen is “-“. This should not be confused with the symbol for a dash, which is the longer “—”.

If you are attempting to indicate a pause within a sentence or add a parenthetical statement to a sentence, you should use a dash instead of a hyphen. An example of a sentence with a dash used instead of a hyphen would be as follows:

  • The three new recruits—Chloe, John, and Michael—were hard workers and a great addition to the team.


1 Merriam-Webster. “Hyphen.” Accessed September 01, 2022. https://www.merriam-webster.com/dictionary/hyphen.

2 Grammarly. “Hyphen.” Accessed September 01, 2022. https://www.grammarly.com/blog/hyphen/.

3 Dirk. “Hyphen-connected participles.” Review editing. July 26, 2012. https://reviewediting.wordpress.com/2012/07/26/hyphen-connected-participles/.

4 Jamieson, Phil. “Master Prefixes and Suffixes with Hyphens.” Grammar Phile Blog. December 08, 2017. https://www.proofreadnow.com/blog/master-prefixes-and-suffixes-with-hyphens.