This came up today because I couldn't determine if "handwriting" should be written as "hand writing" or "handwriting". I know now it's "handwriting". I also forgot that "cannot" shouldn't be written as "can not". What's the rule for compound words? How can I know when something should be a closed compound or not?

  • 4
    A dictionary is always helpful.
    – Greybeard
    Aug 2, 2022 at 23:43
  • 1
    There is no such general rule. You can use "book shop" or "bookshop".
    – Peter
    Aug 3, 2022 at 1:26
  • Isn't there a canonical question for this? Related (2020): Is there a general rule for the usage of hyphens in compound words? Aug 6, 2022 at 11:01
  • No, I'm not talking about hyphens here. I'm asking if there is a spelling rule that might help me remember that cannot is not spelled can not. Why do we do that? Aug 8, 2022 at 23:44
  • 1
    There is a specific question here about cannot, which is slightly unusual. There isn't a general rule: words are normally hyphenated or written with spaces if they are less common compounds, but become closed (like chickpea) if they are more popular, although hyphens can be used to avoid ambiguity or to avoid very long words. Dictionaries have different opinions, but you can consult them. If you are writing to a style guide, it may specify which dictionary to use. English has no set rules.
    – Stuart F
    Aug 9, 2022 at 11:12


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