A hyphen is a punctuation mark that joins words or phrases. Here are some examples of its uses:

Compound adjectives

Joining two or more words to form an adjective:

• Door-to-door selling
• Business-to-business marketing
• School-going children
• Easy-to-use recipe
• Long-term insurance
• Bullet-proof vest

Compound nouns

• Editor-in-chief
• Son-in-law
• Get-together

Prefixes

• Ex-wife
• Non-executive
• Co-worker

Ages

Hyphenate before the noun but not after:

• A 70-year-old woman (an adjective phrase).
• My son is three years old.

Numbers

• Compound numbers from twenty-one to ninety-nine.
• Fractions: three-quarters, two-thirds.
• Numbers that are part of compound adjectives: 500-metre race; 40-hour working week.

Avoid ambiguity

The meaning of words can be different with or without a hyphen:

• I need to recover the money my brother borrowed from me (get it back) before I can afford to re-cover my dining chairs (put on new covers).

Other

• Hyphens are used to indicate the division of a word at the end of a line.
• Hyphens can also indicate a missing element: medium- to long-term.

The evolution of words: Sometimes hyphenated, sometimes not

The prefix “e” stands for “electronic” in e-book, e-reader, and e-mail. But writing changes. The contemporary way to write “email” is without the hyphen.

• Many new words transition from two words, to hyphenated, and then to one word: online, website, worldwide.
• Sometimes they even skip the hyphenated phase: data base/database; health care/healthcare.
• Often both options are still used: co-operation and cooperation.

When there are different spelling options, decide which one you prefer and use it consistently.

© Andrea Paulsen