What is a Hyphen?
A hyphen (-) is a punctuation mark that is used to link words that function together in a sentence or phrase.
The word is derived from Ancient Greek, with hyphen meaning “in one,” as in combining two words in one.
The hyphen is used to avoid ambiguity in writing and to avoid awkward or unnatural combinations of letters.
You see hyphens everywhere━in advertisements, books, messages. It’s a familiar sign, but one that can be tricky to fully understand.
If you’re sitting there wondering, “When do I use a hyphen and when do I not use a hyphen?”, read on. We’re going to cover all things hyphen-related, from rules to examples to the hyphen’s relation to other punctuation.
Hyphen Usage and Rules
There are many instances that call for the use of a hyphen, including (but not limited to) prefixes, compound numbers, descriptors, and line breaks.
The main thing to remember when determining whether or not a hyphen is the appropriate punctuation mark for any given use is that the words being combined must work together to describe or modify a noun.
Hyphen in a Sentence
To hyphenate or not to hyphenate? That is the question.
The answer to this depends on the structure of the sentence itself and is determined largely by the place of the noun in the sentence. Let’s take a look at when to use a hyphen in a sentence and how you’ll go about adding one.
Hyphen with Compound Modifiers: Two-Word Adjectives Before Nouns
Use a hyphen to connect two words that are used as a single adjective before a noun.
Example: The well-adjusted student performed excellently on her exams.
An eight-year-old boy is flying his kite.
A hyphen is not needed if the compound modifier comes after the noun.
Example: The student who performed excellently on her exams is well adjusted.
The boy at the park is eight years old.
Hyphen With a Noun, Adjective Or Adverb and a Present Participle
A present participle is a word that ends in -ing. When a noun or an adjective is combined with one of these -ing words, the unit must be hyphenated. Much like compound modifiers, the hyphen is used before the noun, not after.
Example: The fast-flowing water carried the fish down the stream.
The water in the stream was fast flowing.
Hyphen vs. Dash
Hyphens and dashes are often used interchangeably, but they should not be. A hyphen is used to link compound words and numbers, but dashes have their own specific uses.
The difference between a hyphen and a dash is subtle, but important.
An en-dash (–) is used to show a range of numbers, such as page numbers or times. It can also be used to articulate ideas that don’t include traditional compound modifiers (think of the en-dash as a stronger hyphen).
Examples: People in the United States were able to drink alcohol again post–Prohibition.
The soccer practice runs from 6:15–7:15.
An em-dash (—) is used to illustrate a pause, to show dialogue has been cut off, or to add an aside to an already-established statement. In the latter sense, it can replace commas to show a stronger break in a sentence.
Example: “I don’t have my ticket, but—” The bus shut its doors and drove away without me.
The old dog—whose tail never stopped wagging—walked up to the mailman to be pet.
Hyphen vs. Comma
An easy way to remember the difference between a hyphen and a comma (,) is to think about a hyphen as joining two things, while a comma separates two things. A hyphen links two words together to create one adjective or unit. A comma is used to separate parts of a sentence, such as clauses or listed items.
Example: When I’m sick, I like to eat soup.
If you’re going to the store, can you buy me a box of cereal?
My famously-green grass is envied by all of my neighbors.
Hyphen vs. Semicolon
Much like a comma, a semicolon (;) serves a purpose very different from that of a hyphen, though they are sometimes confused.
A semicolon is used to connect two independent clauses, which are each a complete thought. These clauses are either of equal rank or closely related.
Whereas hyphens connect words, semicolons connect whole ideas and clauses, which could themselves be their own, usually short, sentences.
A semicolon can come after a complete thought and has a space after it. The first letter of the first word of the second clause is never capitalized when using a semicolon, though. A hyphen will be in between two words with no spaces surrounding it.
Example: A lot of books tell stories; however, not many books can move you to tears.
I want to swim across the ocean; my mother doesn’t think it’s such a good idea.
My favorite part of the circus is the high-wire act.
Hyphen vs. Colon
A colon (:) is used to make lists or to separate independent clauses when the second explains the first.
If you remember that hyphens are used in between two words and never two clauses, you will not have any trouble distinguishing between these two punctuation marks.
Example: I have three kinds of ice cream: vanilla, chocolate, and strawberry.
Her dream had finally come true: she was moving to Hollywood!
Hyphenated Words and Examples
Now that we’ve learned when and how to use a hyphen, let’s focus on some examples of hyphenated words. Hyphenation is one way to create a compound word, which is created by combining two words to make a new word.
In this article, we have focused on compound modifiers, which are used before a noun. Here are some examples of compound modifiers/hyphenated adjectives:
We can also create compound nouns through hyphenation. As with adjectives, we just take two words and join them using the hyphen. There is no hard-and-fast rule to determine whether or not a compound noun should be hyphenated; it is an irregular phenomenon. However, using a dictionary can help to clear confusion over whether or not a compound noun should be open, closed, or hyphenated.
Here are some examples of hyphenated compound nouns:
Closed Compound Words
Not all compound words are hyphenated. As important as it is to learn which words get a hyphen, it is equally important to see which ones don't.
A closed compound word is two words joined together without a space or hyphen in between. Here are some examples:
- Classmate (Class + mate)
- Bedroom (Bed + room)
- Penpal (Pen + pal)
- Skateboard (Skate + board)
Open Compound Words
Open compound words are just like closed compound words, except they do have a space in between the two smaller words, where the hyphen would go in hyphenated compound words.
Here are some examples:
- Ice cream
- High school
- French fries
- Living room
Open compound words are technically two separate words, but because their meaning applies to both of the words only when they are combined, they are considered to be a single compound word.
Hyphens and Numbers
Hyphens are also used when writing out numbers. Not all numbers get hyphenated, so these rules will help you when determining which ones do and which ones do not.
Hyphen in Compound Adjective with Numbers
- Hyphenate all compound numbers (consisting of two words) between 21 and 99, except for 30, 40, 50, 60, 70, 80, and 90 (because these are only one word). Examples: sixty-seven; thirty-eight; forty; eighty-two
- Numbers below 21 and over 99 do not need a hyphen. Examples: twelve, one hundred, two
- If the number is over 100 and includes a compound number, you only hyphenate the compound number. Examples: nineteen twenty-seven; two hundred and fifty-three
Hyphen in Compound Adjective with Fractions
When fractions are written out and used as adjectives, they are always hyphenated.
- She was three-quarters Scottish.
- The recipe calls for two-fifths of a cup of honey.
- One-half of the student body went to the football game.
Hyphens with Prefixes
Some prefixes require a hyphen while others don't. Luckily, there are a few rules to go by when deciding if a word with a prefix needs a hyphen or not.
- Hyphenate if the word is capitalized. Example: anti-American
- Hyphenate if the prefix ends with a vowel and the word begins with a vowel. Example: co-owner
- Hyphenate if not including a hyphen would create another word. Example: re-press (not to be confused with repress)
If these rules seem overwhelming, make sure to use an online grammar checker to double check your punctuation usage.
Hyphens with High or Low
Compound words that include high and low should always be hyphenated.
- High-interest credit cards can rack up a lot of debt.
- Low-hanging clouds are hazardous for pilots.
- I live in a high-income area.
- The low-resolution video is hard to watch.
Hyphens can be tricky because they are easily confused with several other types of punctuation marks, but thankfully, now you have a handy resource for understanding the differences, both big and small.