Oh, Dash It! They All Look the Same!
The em dash is my favorite piece of punctuation. It’s sleek and sexy and a little bit mysterious. They’re constantly mistaken for an en dash or a hyphen—it’s like they have an identity crisis! While it seems like such an incremental difference, each punctuation has a different meaning, so it’s important for copy editors and authors to know the difference between the three.
Notice the difference in line length:
Em dash: —
En dash: –
Hyphen: –
It’s usually the en dash and the hyphen that get confused, but we’ll briefly overview how each dash is meant to be used. You’ll be a lifesaver to your editor if you write them correctly the first time!
Em Dash
Keyboard Shortcut: (Alt + 0151)
The em dash is used to replace other forms of punctuation, such as commas, parentheses, colons, and semicolons. However, you’d favor the em dash over these other punctuation marks to make special emphasis to the reader. For instance, you’d use em dashes to make an interjection, explain something, supply additional information, or make commentary.
Ex: The waves of her hair—long strands of shimmering gold—were wrapped in a braid down her back.
In this example, the phrase enclosed in the em dash is set aside as an interjection to the rest of the sentence. The interjection doesn’t function as a grammatical part to the independent clause on that sentence, so it has to be set apart. It’s also important to note that the independent clause on either side of the em dashes must still be a complete sentence if the interjection were to be taken out. That means the verbs on the right side (were) are bound to the subject on the left side (the waves of her hair), not the subject inside the em dashes.
The wonderful thing about em dashes is that you can also make long interjections that take advantage of other bits of punctuation.
Ex: The waves of her hair—long, bountiful strands of shimmering gold that reminded Hayden of cornfields—were wrapped in a braid down her back.
Notice how this interjection is longer and uses a comma. This is just one example of how interjections can use a comma, but you can also create lists or even have a tangle of dependent clauses within the em dash enclosure.
Em dashes can also tail the end of a sentence.
Ex: The waves of her hair were wrapped in a braid down her back—like the shimmering gold of cornfields.
This use of the em dash is more of an aside, where the information isn’t necessary to the grammatical sentence, but it supplies additional sensory information that helps the reader visualize the girl.
En Dash
Keyboard Shortcut: (Alt + 0150)
If em dashes are the sexy, long legged punctuation, then en dashes are the slightly stouter cousin that everyone forgets about. En dashes are used for two reasons: 1) in numerical ranges, and 2) to replace a hyphen in a compound adjective.
Numerical Ranges
En dashes are used to express negative numbers (–79) or show subtraction in a mathematical equation (5 – 2 = 3). However, they are also used as a stand in for the word through in numerical ranges. So, if you need to write a date, you would use an en dash:
February 20–February 25, or pages 20–25
When you read this, your brain should automatically understand that the en dash means February 20 through February 25, or pages 20 through 25. However, you would not used an en dash in an instance where the word from precedes the numerical range. If we rephrased this example to from February 20 to February 25, then an en dash would not be correct in shorthand because this range doesn’t include the word through.
Compound Adjective
En dashes can also be used to replace a hyphen in a compound adjective, meaning that one part of the adjective is already hyphenated. An example would be high-value–low-cost. The words high-value and low-cost are each independent adjectives that are already hyphenated, so the en dash fuses the two hyphenated terms together to make a single compound adjective.
Similarly, en dashes can be used to combine one term in the compound to another term that is two to three words (post–World War II).
Hyphen
Keyboard: The small dash key (-) next to the 0 on the keyboard
A hyphen’s most used function is to connect words. However, there are some rules that dictate whether words can be hyphenated or not, so we’ll just briefly catalogue these.
Compound Nouns
When we think of hyphenated words, compound nouns are usually what our brains flick to. These are words like mother-in-law, twelve-year-old, twenty-two-year-old, etc. However, it’s common for people to confuse a hyphenated compound for a closed compound (bookbag) or an open compound (tennis shoe). If you’re unsure what category a word falls under, it’s easiest to consult a dictionary.
Compound Adjectives
Usually, hyphens are used to connect words that function together as one adjective, e.g. dog-friendly, one-of-a-kind, high-level, self-paced, etc. However, let’s look at how these are written based on their placement in a sentence.
Ex: This hike is dog friendly. vs. I’m trying to find a dog-friendly hike.
Notice that the first sentence is unhyphenated while the second sentence is hyphenated. That is based on the placement of the noun (hike) that the adjective (dog-friendly) it is modifying. In the first sentence, the noun is before the adjective, meaning it doesn’t get hyphenated. In the second sentence, the noun is after the adjective, meaning that it does get hyphenated.
Hyphenated Participles
Participles follow the same grammatical rules as compound adjectives in that the modifier should only be hyphenated if it comes before the noun.
You would use a hyphen to connect a noun, adjective, or adverb to a present participle (verbs ending with -ing) that is describing or modifying a different word.
Ex: The hike had a foul-smelling odor.
Notice how foul-smelling needs to be connected to modify the word odor.
You may also use a hyphen to connect modifiers with a past participle (verbs ending in -ed or other irregular verb endings).
Ex: This is a well-known trail for hikers with dogs.
Prefixes
Prefixes—those short attachments at the beginning of a root word that give it a new meaning—should be hyphenated in a few different circumstances:
- Prefixes should be hyphenated in a word when there is a chance the word could be misread if otherwise not included: re-create
- You may also use the prefix if it precedes a proper noun: trans-Atlantic
- They avoid double vowels: non-negotiable
- There are also some prefixes that automatically pair with a hyphen: ex-, self-, all- / ex-wife, self-taught, all-encompassing
All of these instances use hyphenated prefixes to provide clarity on the meaning of the word being added to.
