Hyphens (-) are the short lines that we put between words.
- Two-word compound adjectives are hyphenated when the second word ends in -ed or -ing.
Other two-word adjectives which contain the sense of ‘between’ are also often hyphenated.
blue-green (between blue and green)
The New York-Paris flight.
Longer phrases used as adjectives before nouns are also often hyphenated.
an out-of-work singer
Two-word compound nouns are hyphenated when the first word is stressed.
The prefixes co-, non- and ex- are sometimes separated from what follows by hyphens
Nowadays there is a growing tendency to avoid hyphens. Most common short compounds are now written as single words with no separation between them.
Less common or larger compounds are written as completely separate words.