The hyphen is primarily used to form compound words, and it also has a role in word division. It’s important to remember that a hyphen should never replace an en dash (–) or an em dash (—).
1. Compound Terms
Compound terms consist of multiple words that represent a single item or idea. They can be categorized into three styles:
A. Open (or Spaced) Compounds
These are written as separate words.
Examples:
- high school
- ice cream
- post office
B. Hyphenated Compounds
These use hyphens between the words.
Examples:
- sister-in-law
- runner-up
- state-of-the-art
C. Closed (or Solid) Compounds
These are written as a single word.
Examples:
- toothpaste
- basketball
- wallpaper
2. Compound Nouns
Compound nouns can often be found in a good dictionary. Many start out as spaced or hyphenated before becoming solid over time.
Examples:
- firefly (initially may have been written as fire fly or fire-fly)
- passport
- toothbrush
3. Compound Verbs
Many compound verbs are included in dictionaries and generally retain their hyphenated form.
Examples:
- babysit
- overcook
- brainstorm
4. Compound Adjectives
Compound adjectives are more complex and often depend on their position within a sentence. The following rules can help determine when to hyphenate:
- Hyphenate compound adjectives when they appear before a noun.
Examples:
- We need a well-organized plan.
- She is a fast-paced writer.
- Do not hyphenate compound adjectives when they appear after a noun.
Examples:
- The plan was well organized.
- The writer is fast paced.
- Adverbs ending in -ly are not hyphenated.
Examples:
- She is a beautifully painted mural.
- It was a highly regarded film.
- If an adverb is part of a larger compound adjective, use a hyphen.
Example:
- They had a not-so-fun experience.
5. Forming Compounds with an En Dash
Certain complex compounds may use an en dash instead of a hyphen, particularly when indicating a range or connection between two elements.
Example:
- The New York–London flight was delayed.
6. Word Division
The hyphen can be used to divide words at the end of a line. This is more relevant in professionally printed materials. For most personal or academic writing, word division is typically handled automatically by word processors.
Example:
- This is an ex- ample of word division.
Common Mistakes to Avoid
- Using a Hyphen Instead of an En Dash or Em Dash
Incorrect:
- The conference will take place on June 5-7.
Correct:
- The conference will take place on June 5–7.
- Hyphenating Words Incorrectly
Incorrect:
- He is a highschool teacher.
Correct:
- He is a high-school teacher.