Hyphens between Words

When to Use a Hyphen between Words

Hyphens are used to join words to show the reader they are the same entity. For example:

• I am seeking a six-fingered man.
(The hyphen joins "six" and "fingered" to show the two words are one entity, i.e., one adjective.)
• Dentists use laughing-gas.
(The hyphen joins "laughing" and "gas" to show the two words are one entity, i.e., one noun.)

So, hyphens are joiners. Dashes, on the other hand, are separators.

When To Use a Hyphen

Hyphens have two main functions:

(1) To join words to show they are a single entity.

• ice-axe
(This is one thing. The hyphen makes it clear that we're not talking about an axe made of ice.)
• cooking-oil
(This is one thing. The hyphen makes it clear that oil is not cooking, i.e., getting hot)
• free-range eggs
("Free-range" is one adjective. The hyphen makes it clear that the eggs are not free. It also makes the text easier to read.)
• twenty four-page leaflets
("Four-page" is one adjective. The hyphen makes it clear that each leaflet has four pages. It also makes the text easier to read.)

"Ice-axe" and "cooking-oil" are classified as compound nouns (a noun consisting of more than one word). "Free-range" and "four-page" are called compound adjectives (an adjective consisting of more than one word).

(2) To join a prefix to a word root for clarity or readability.

• re-press
(The hyphen makes it clear that the meaning is "to press again" and not "repress" as in "to put down by force.")
• re-establish
(This is easier to read than "reestablish.")

Read more about using hyphens.

Nine Ways to Use Hyphens between Words

Listed below are the nine ways to use hyphens:

(1) To form a compound noun.

• Being married means I can eat ice-cream in bed. (Actor Brad Pitt)
• Pass me the plastic wire-fastener.

(2) To form a compound adjective.

• It's only a three-seater aircraft.
• It will be a never-to-be-forgotten experience.
• They had a twenty-year-old cat.

(3) To remove ambiguity with adjectives.

• It is a heavy-metal detector.
(The hyphen makes it clear the device detects heavy metals as opposed to being a heavy device.)
• It is a broken-heart pendant.
(The hyphen makes it clear the pendant is of a broken heart as opposed to being a broken pendant.)

(4) To remove ambiguity with adverbs.

• He is the best-known actor.
(The hyphen makes it clear he is not the best actor of the known actors.)
• There are more-important things in life.
(The hyphen makes it clear that more modifies important and not things.)

Note: Do not join an adverb to an adjective unless it eliminates ambiguity.

• She is an extremely-happy dog.
• She is a very-happy dog.

(5) To form an original compound verb.

• The winner typically cheese-chases at 20 mph.
• He needed to gate-vault the obstacle.
• James spent the evening in hospital after he happy-slapped a bystander, who turned out to be a champion boxer.

(6) To form an original compound noun.

• This issue is a real no-brainer.

(7) When writing numbers in full.

• three hundred twenty-four
• sixty-one

Note: Use a hyphen for all numbers between 21 and 99 (less those divisible by 10, e.g., 30, 40).

(8) When writing fractions in full.

• four-fifths
• two-thirds

(9) With some prefixes.

• anti-aircraft
• cooperate

Read the guidelines for using hyphens in prefixes.

Hyphens Are Not Meant to be Used for Ranges

Hyphens are not meant to be used for ranges (e.g., 12-14, 2001- 2010). Dashes are used for this purpose. However, given that the hyphen is so easy to find on a keyboard, hyphens have become acceptable for ranges. Only a very strict grammar pedant would chastise you for using hyphens. If this were to happen, you could make a good case for the pedant being out of date. Read about dashes between numbers.

The Different Types of Dash

The table below shows the four main dash-like characters ordered longest to shortest. Note that hyphens are shorter than dashes.

Name	Punctuation	How To Get One
em dash	—	Ctl + Alt + minus (on the numeric pad)
minus sign	−	minus (on the numeric pad)
en dash	–	Ctl + minus (on the numeric pad)
hyphen	-	- (the key to the right of "0")

Read about using dashes.