How to spell compounds

Compounds are words formed from two (or more) words. For example, black + board = blackboard.

They can be spelled in three ways:

  1. as a single word: flowerpot
  2. as two words: flower pot
  3. with a hyphen: flower-pot

So which one should you choose? A linguist has devised a rule which she says works for 75% of words:

  • Compound verbs, adjectives and adverbs – use a hyphen (blow-dry, world-famous, well-nigh)
  • Compound nouns:
    • 3+ syllables – use a space (bathing suit)
    • 2 syllables:
      • second part has 2 letters – use a hyphen (make-up)
      • second part has 3+ letters – as a single word (coastline).

You can read more on her website.

My even simpler rule: if you’re not sure, write it as a single word: blowdry, worldfamous, wellnigh, bathingsuit and makeup. Even if it’s wrong, it looks cuttingedge.