For example, "file system" and "related". Is it "file system-related"? It will appear as if it is a compound of "file" and "system-related", won't it?


3 Answers 3


This is a very good question and is one that troubled me for a long time.

Here is what the Fowler brothers say in their Kings English:

TEXT 1: Within the last ten days two Anglo-South Americans have been in my office arranging for passages to New Zealand.—Times.

SUGGESTION 1: Anglo-South-Americans is the best that can be done. What is really wanted is Anglo-SouthAmericans, to show that South goes more closely with America. But it is too hopelessly contrary to usage at present.

TEXT 2: The proceeds of the recent London-New York loan.—Times.

SUGGESTION 2: London and New-York loan.

TEXT 3: A good, generous, King Mark-like sort of man.—Times.

SUGGESTION 3: King-Mark-like, in default of KingMark-like. But the addition of -like to compound names should be avoided.

TEXT 4: The Fugitive Slave-law in America before the rebellion.—H. Sidgwick.

SUGGESTION 4: Fugitive-Slave law

In answer to your question, based on Fowler's advice (which I find practical and logical), I would write filesystem-related or file-system-related, e.g., 'Please remember that this is a filesystem-related job.'

  • 3
    +1 for filesystem-related, since "filesystem" is commonly a single word in computer contexts.
    – psmears
    Commented Jan 16, 2011 at 12:38
  • 7
    Personally, I find all of the above "King's English" suggestions horrible, and #4 should rather suggest no hyphen at all.
    – Erich
    Commented Feb 12, 2015 at 23:41
  • 3
    I agree with suggestions 1 and 3, but I think the other two are bad. There’s no reason to hyphenate “New-York” at all in #2, and the resulting sentence is ungrammatical. In #4, the author is blindly ignoring the fact that “Fugitive Slave Law” is a proper noun. The problem is the attempt to hyphenate at all. Commented Nov 26, 2017 at 5:24

You're looking at a compound compound modifier.

Generally, a compound modifier (a two-word phrase that is used as an adjective) is hyphenated when it appears before the noun it is modifying:

  • The brick-oven pizza was cooked in a brick oven.
  • Love is a two-way street.

The hyphen is there to prevent confusion on which words are being modified. There may be more important reasons, but this is the more-important reason.

Each of the components of a compound adjective can itself be a compound word. It is common in this case to use an "en dash" to keep things well organized:

  • I plan to open a brick-oven–pizza restaurant.
  • All file-system–related software has to be cleared by IT.
  • 2
    It's unnecessary-to-wrong to hyphenate 'more important' even when used attributively. See eg the NG Style Manual (2b), but there are even more authoritative sources who say this. Commented Oct 8, 2014 at 11:06
  • @Edwin Ashworth: I think that if the writer means to say "There are additional reasons that are (also) important," the better way to express this in short form is to omit the hyphen from the sentence: "There are more important reasons." But if the writer means to say "There are reasons more important than the ones heretofore identified," the better way is to add the hyphen to the sentence: "There are more-important reasons." CMOS, 15th ed., 7.85, and Oxford Style Manual, 5.10.1, seem to endorse this distinction. But you're right about "more important reason," which can't be misread.
    – Sven Yargs
    Commented Oct 11, 2014 at 4:27
  • 1
    @Sven: Yes; I'll moderate 'unnecessary-to-wrong' to 'often, arguably always, unnecessary'. Wikipedia has: '... However, if the compound is a familiar one, it is usually unhyphenated. For example, at least one style guide prefers the construction high school students, to high-school students.[8] Although the expression is technically ambiguous ("students of a high school"/"school students who are high"), it would normally be formulated differently if other than the first meaning were intended.... Commented Oct 11, 2014 at 7:44
  • 1
    And 'However, if [an adjective-modifier] can also function as [a quantifier], then a hyphen may be or should be used for clarity, depending on the style guide. For example, the phrase more-important reasons (reasons that are more important) [may be] distinguished from more important reasons (additional important reasons), where more is [a quantifier].' [Parts of speech adjusted / corrected.] In a Google search for "more important reasons", both of the above usages (and one or two others) appear in profusion. Though sometimes the ambiguity is technically possible, hyphens are extremely rare. Commented Oct 11, 2014 at 7:54
  • 1
    @user3932000 I decided it deeded de-garden-pathing.here. Commented Jul 23, 2019 at 13:21

All style guides rule that <file-system-related> is perfectly fine and grammatical. (Just hit up Google, 100 of 100 guides rule so, eg §§.)

It's a misconception [cf] that multiple dash marks is wrong. Apparently/ presumably, dash marks are seen as unconventional/ nonacademic because newspapers don't use them. Yet that's only because of width limits, not correctness [–cf].

Some examples of equal syntax:

  • <self-driving-car tutorial> [<self-driving> is perceived as an independent unit]

  • <non-self-governing tutorial> [<self-governing>]

  • <non-profit-making tutorial> [<profit-making>]

  • <non-self-sustaining tutorial> [<self-sustaining>]

  • <non-life-threatening tutorial> [<life-threatening>]

  • <anti-child-abuse tutorial> [cf] [<child-abuse>]

  • <anti-social-justice tutorial> [<social-justice>]

  • <two-foot-long tutorial> [<two-foot>]

  • <nine-year-old tutorial> [<nine-year>]

  • <Paris-Principles-compliant tutorial> [<Paris-Principles>]

  • <come-as-you-are tutorial> [<as-you-are>]

  • <two-and-a-half-hour tutorial> [<a-half>, <two-and-a-half>]

  • <jack-in-the-box tutorial> [<the-box>]

  • <state-of-the-art tutorial> [<the-art>]

  • <five-and-one-half-foot-long tutorial> [<one-half>, <five-and-one-half>, <five-and-one-half-foot>]

  • <great-great-grandfather tutorial> [either <great-great> or <great-grandfather>]

Acceptors' acceptance / grammar-correctness aside, when/ if multiple hyphens exceed the desired [dependent on protocol [usually dependent on author and audience]] threshold of equivocation [cf †1, †2], prefer either of:

  1. <filesystem-related> [nb, first dash mark is omitted, thus clear that <file> and <system> are grouped before <related>]
  2. <file-systemrelated> [nb, second dash mark <–> is elongated, thus clear]

    ( ..This can be typeset using an “endash”:

    • Windows: Hold down alt and type 0 1 5 0 using the numpad [right-side] of the keyboard.
    • Mac: Hold down Option and type the minus sign.
    • Present-day browsers: URL data:text/html,&ndash;.
    .. )

  3. <file-system--related> [nb, second dash mark is "doubled", thus clear]

    (Nb in some in-text contexts, this equivocates an “emdash” as it's the same mark [cf †1, †2, †3, †4, †5, †6])

Indeed, some/many publisher(s) require such preferences, eg English Wikipedia (the modern authority on English writing style (cf)) requires rejection of the syntax of <file-system-related> in favor of that of <file-system–related> [elongated second dash mark].

Bonus section:

English Wikipedia niceties per §:

  1. When/ if the concept [cf] within the author’s mind is referred by the print <w1>, then said print refers to 100% of the concept.
  • When/ if <w1-w2> then {{<w1>, <w2>}} refers to 1⁄2 [50%] of the concept.
  • When/ if <w1-w2-w3> then {{<w1>, <w2>, <w3>}}, 1⁄3 [~33.33%].
  • Examples:
    • <brother-in-law>
    • <up-to-date>
    • <tried-and-tested>
    • <hard-and-fast>
    • <all-or-nothing>
    • <look-it-up>
    • <devil-may-care>
    • <happy-go-lucky>
    • <fly-by-night>
  1. This has no theoretical length limit.

    ..When/ if <w1-w2-w3-w4-w5-w6-w7-w8-w9-w10> then each <w> refers to 1⁄10 [10%] of the concept, eg <a using-many-dashes-for-the-sake-of-using-many-dashes example> [cf].

  1. To assign a particular <w> more weightage, use a longer dash mark:
    • w1w2-w3

      ..which gives <w1> 1⁄2, and {{<w2>, <w3>}} 1⁄2 of 1⁄2 [—25%] of the concept.

    • w1-w2w3

      ..which gives <w3> 1⁄2, and {{<w1>, <w2>}} 1⁄2 of 1⁄2.

    • w1-w2w3-w4

      ..which gives {{<w1-w2>, <w3-w4>}} 1⁄2, and {{<w1>, <w2>, <w3>, <w4>}} 1⁄2 of 1⁄2.

  • Re <w1-w2-w3-w4> [A] vs <w1-w2w3-w4> [B]:
    • A: Each <w> is a 1st-level unit.
    • B: {{<w1-w2>, <w3-w4>}} is a 1st-level unit, Each <w> is a 2nd-level unit.
  • Re <pro-establishment–anti-intellectual alliance>:
    • <pro> is grouped with <establishment>.
    • <anti> with <intellectual>.

    A meaning-gap [“firewall”] is between items in separate groups:
    • {{<pro>, <establishment>}} on its own has nothing to do with {{<anti>, <intellectual>}}.
  • A long example:
    • {{<w1>, <w2>}} refers to 1⁄2 of 1⁄5 of the concept.
    • {{<w3>}}, 1⁄5.
    • {{<w4>, <w5>, <w6>}}, 1⁄3 of 1⁄5.
    • {{<w7>}}, 1⁄5.
    • {{<w8>}}, 1⁄5.
  • 3
    Your alternative option 1., discarding the hyphen in favour of writing the compound closed is always wrong. Filesystem-related would not be accepted by any style guide, and cases selfdriving-car, non-lifethreatening, ParisPrinciples-compliant, and twoandahalf-hour are downright bizarre and would be rejected not only by any style guide, but also by any reader. The only cases where writing an attributive or nested compound closed are those where the compound can always be written closed, such as bookshelf or handgun. Commented Sep 2, 2017 at 14:23
  • @Janus, Style guides have only one rule—"reject ambiguity". Everything else is accepted in varying degrees from 0% to 100%—inventing compounds to remove ambiguity is definitely valid in all style guides. ¶ And your examples look weird by themselves only because no ambiguity can be caused by writing them the typical way—eg capitalization of <Paris Principles> already removes ambiguity in nearly all cases, thus there's no need to compound it. ¶ But say, inventing a compound <antihard> in <antihard-and-fast worker> is valid because <anti-hard-and-fast worker> is ambiguous.
    – Pacerier
    Commented Sep 20, 2017 at 17:53
  • 3
    No, on all counts. Style guides have many, many rules, and “reject ambiguity” is certainly not common to all of them. In fact I doubt any of them would have that as a rule. “Avoid ambiguity” is a very common piece of advice found in style guides, but I have never seen it presented as a rule in any. I'd like to see you present just one style guide that would allow closing up attributive compounds that are not written closed predicatively. Commented Sep 20, 2017 at 17:56
  • @JanusBahsJacquet, I'd like see just one style guide that forbids so, especially in the event that the sentence has no clearer alternatives. ¶ Re "reject ambiguity" Have you seen style guides recommending clarity as the overarching general rule? A-plenty. Reducing ambiguity increases clarity; Increasing clarity reduces ambiguity. Yes-way.
    – Pacerier
    Commented Oct 3, 2017 at 9:35
  • 3
    Like I said, style guides nearly always advise avoiding ambiguity. You have still not provided a single style guide that makes it a rule. You’re the one claiming that closing up compounds willy-nilly is supported by style guides; the onus is thus on you to provide evidence that even a single style guide gives any such support. Chicago, for example, explicitly advise opting for open compounds, not closed. Commented Oct 3, 2017 at 9:45

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