A sentence may contain two nouns back-to-back. How are these nouns written together?

  • I went to that book store.
  • I went to that bookstore.
  • I went to that book-store.

Why can these two nouns be adjacent to each other without being combined or without added punctuation?

balloon sleeves

Is it acceptable to write the two nouns like either of the following? Why or why not?

  • balloon-sleeves
  • balloonsleeves

But what about this:

”. . .I am opening the flood-gates myself. . .”?

Which is grammatically correct?

  • flood-gates
  • floodgates

Does the correct manner in which "flood gates" is written apply to all pairs of adjacent nouns?

  • 4
    You don't need the words "may" and "maybe" nearly as much as you appear to think. Use "can" or "do" or various forms of those verbs instead of writing "may", and leave out "maybe" entirely. Jul 9, 2015 at 2:15
  • Technically, these are not two nouns. They are an adjective and a noun. Like in "book store", "store" is a noun, but "book" is serving as an adjective to say what kind of store. Not that this answers your question so I'm making it a comment.
    – Jay
    Jul 9, 2015 at 22:08
  • I think I thought something like that, Jay. I maybe thought some seem more like adjectives, like maybe book store, book-store, bookstore, book I think seems to place information on what store. May flood-gates, floodgates seem different? I don't think I may frequently observe flood like an adjective. I like that information. I thank you, Jay.
    – saySay
    Jul 9, 2015 at 22:26
  • 1
    No, there are no adjectives here. Words like bookstore and floodgate are noun-noun compounds.
    – user230
    Jul 10, 2015 at 13:53

2 Answers 2


The general rule for noun phrases like this is to separate them by spaces.

However, many* specific pairs of words have exceptions and are either written hyphenated, or are even merged into a new word with no separation at all. For example, "copy editor" is in the process of moving from unhyphenated noun phrase through hyphenated noun phrase to new word, although at present all three forms are more or less acceptable.

Your specific examples are customarily written like this:

  • "bookstore" (although "book store" is acceptable; "book-store" looks odd, as though you had realized it was a very common phrase but hadn't realized it was so common it was its own word already)
  • "balloon sleeves" (and only that way: it's just not very common)
  • "floodgates" (it's been a single word for centuries, so even "flood gates" seems a bit off)

*Very many. Seriously, there are a lot. Noun phrase collocations are quite common.

  • So I guess these seem like noun phrases. So there may seem no set thing to discern if two nouns get written like two words, if you may hyphenate them or if they get written like one word? Like there may seem no set thing why bus stop may not get written like busstop? And may you get to write language-lover like one word? I may not get why you maybe may not get to hyphenate this. It seems like one thing, so I may guess one word (one noun[?]{person, place or thing}[?])?
    – saySay
    Jul 9, 2015 at 20:51
  • And I guess I may not get why you may write teacup and not coffeecup, or why you may not hyphenate them both like tea-cup, and coffee-cup?
    – saySay
    Jul 9, 2015 at 20:52
  • "teacup" has been in use long enough as a set phrase that we more or less arbitrarily decided it was a single word now. "coffee cup" hasn't gotten to the hyphenation stage yet. Basically, it just depends on how often the phrase shows up together -- there's no real heuristic otherwise. That said, you'll rarely go too far amiss if you simply stick to the basic pattern of "tea cup", "milk maid", and so forth. (Hyphenation is not the default, and it usually looks weird if it's not customary. But separation with a space doesn't look as weird, even if it's customary to merge the words more.) Jul 9, 2015 at 21:02
  • I've added the examples from your question just in case there's still confusion about them. Jul 9, 2015 at 21:07
  • See also: grammarly.com/handbook/punctuation/hyphen/2/… for hyphen connected phrases.
    – Tiny Giant
    Jul 9, 2015 at 21:19

General rule, there is no rule. When in doubt you have to look up the word to see which spelling is the most common. Sometimes two spellings are used side by side.

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