The hyphen (-) is a punctuation mark used most often to join words or create compound terms. Here are 8 common situations:
1. To form compound adjectives
water-repellent
state-of-the-art
2. To describe familial relations
father-in-law
sister-in-law
3. To show prefixes
semi-permanent
e-book
4. To create an adjective with a suffix
rat-like
cat-like
5. To combine adjectives with nouns to make an adjective
small-town politics
big-city cafés
6. To clarify meaning
A hyphen is often used to help prevent confusion:
Confusing: resave your work on the laptop.
Better: re-save your work on the laptop.
7. To show numbers between twenty-one and ninety-nine
fifty-six
forty-two
8. To write a double name
Mr. John Colvin-Slee.
Dr. Emma May-Watson
Ruby-Grace Gonzalez
Reminders
Careful not to confuse hyphens with the em dash or the en dash, as they have different uses.
Also remember to not surround a hyphen with spaces:
Incorrect: space – walk
Correct: space-walk
When in doubt over whether a hyphen should be used, consult a good dictionary or style guide.