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:
2. Use a hyphen to make compound modifiers before nouns:
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:
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: