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Hyphens 101

Hyphens are surprisingly versatile, but because they are used in so many different ways, there are a lot of rules governing what they can and cannot do. You can often decide to hyphenate or not to hyphenate by assessing whether or not hyphenating would cause confusion or ambiguity. When in doubt, you can also consult a reliable Canadian dictionary or your in-house style guide.

Use hyphens

  • to form compound adjectives, nouns and verbs
    • Professor Chimirri tries not to be long-winded.
    • My great-aunt Joy raises racehorses.
    • Someone hot-wired Naomi's car and abandoned it 60 km out of town.
  • to write out the numbers twenty-one through ninety-nine, as well as expressions of time of day
    • Twenty-two years ago, Marc Garneau became the first Canadian in space.
    • If you run, you might be able to catch the four-thirty bus.
  • to add certain prefixes in the following cases:
    • in titles that begin with vice and then
      • The vice-chair called a meeting.
    • with most prefixes attached to a proper noun or adjective
      • We leave on our trip in mid-June.
    • with ex (in the sense of former), self, quasi and all when forming adjectives and some nouns
      • John's ex-wife Dana prided herself on her self-reliance
  • with most prefixes attached to a proper noun or adjective
    • We leave on our trip in mid-June.
  • with ex (in the sense of former), self, quasi and all when forming adjectives and some nouns
    • John's ex-wife Dana prided herself on her self-reliance.
  • to add certain suffixes, including elect, as well as odd and strong (when attached to a numerical expression)
    • The mayor-elect thanked each of the fifty-odd volunteers who worked on the campaign.
  • to prevent confusion or unintentional vowel doubling
    • In the off-season, the Calgary Flames re-signed (as opposed to "resigned") a number of their young players.
    • They re-examined (as opposed to "reexamined") their roster in light of the previous year's results.
  • to show spelling
    • Does he spell his name S-e-a-n or S-h-a-w-n?

Do NOT use hyphens

  • to form compound modifiers after a noun

    WRONG: On campuses, the band was well-known.

    REVISED: On college campuses, the band was well known.

    OR

    REVISED: On college campuses, they were a well-known band. (compound modifier precedes the noun)

  • to create a compound with an adverb ending in ly

    WRONG: Still heavily-sedated from surgery, the patient struggled to stay awake.

    REVISED: Still heavily sedated from surgery, the patient struggled to stay awake.

  • to join a numerical expression and a possessive noun

    WRONG: Dalibor challenged his friends to donate one-week's pay to the hurricane relief effort.

    REVISED: Dalibor challenged his friends to donate one week's pay to the hurricane relief effort.

  • to write most words beginning with the following prefixes: after, ante, anti, bi, co, counter, de, down, extra, infra, inter, intra, iso, macro, micro, multi, over, photo, poly, post, pre, pro, pseudo, re, retro, semi, stereo, sub, super, trans, tri, ultra, un, under and up (when in doubt, check your dictionary)

    WRONG: A film may reach "cult" status and be generally under-rated or over-looked.

    REVISED: A film may reach "cult" status and be generally underrated or overlooked.

  • to write most words ending with the following suffixes: like (except when a double l would be produced), fold and score (when attached to a numerical expression, unless that expression already has a hyphen)

    WRONG: This year alone, the price of life-like robots has increased at least two-fold.

    REVISED: This year alone, the price of lifelike robots has increased at least twofold.

  • to provide compass directions consisting of two points only

    WRONG: The wind blew south-east at eight kilometres per hour.

    REVISED: The wind blew southeast at eight kilometres per hour.