A hyphen is a very short horizontal line between words.
Note that there is no space between a hyphen and the character on either side of it.
Do not confuse a hyphen (-) with a dash (—), which is longer.
The rules about hyphens are not fixed. The points below are guidelines rather than rules.
1. Use a hyphen to join words to show that their meaning is linked in some way:
- book-case (or bookcase)
- race-horse (or racehorse)
2. Use a hyphen to make compound modifiers before nouns:
- a blue-eyed boy (but The boy was blue eyed.)
- the well-known actor (but The actor is well known.)
- their four-year-old son (but Their son is four years old.)
3. Use a hyphen with certain prefixes. The prefixes all-, ex-, and self- usually need a hyphen:
When a prefix comes before a capitalized word, use a hyphen:
When a prefix is capitalized, use a hyphen:
4. Use a hyphen when writing numbers 21 to 99, and fractions:
- one hundred and sixty-five
5. Use a hyphen to show that a word has been broken at the end of a line (hyphenation):
6. Use a hyphen with "suspended compounds". When we use several very similar compounds together, it may not be necessary to repeat the last part of the compound:
- They need to employ more full- and part-time staff. (not They need to employ more full-time and part-time staff.)
- This rule applies only to 12-, 13- and 14-year olds. (not This rule applies only to 12-year olds, 13-year olds and 14-year olds.)