A construction that I have been seeing a lot lately that seems surprising to me is "The 8-foot-long bridge ...," with two hyphens.

It seems surprising to me (or maybe I'm just noticing it) that there is a second hyphen between "feet" and "long".

Is this considered a common construction or is it more of an accepted though less common use?

  • How would you feel about 8-year-old vs 8-year old? I know of at least one house style that prefers the second option, but I'd always opt for the first. Commented Nov 13, 2014 at 19:39
  • I suppose the first seems more natural. Maybe this is one of those notice it once and then see it everywhere type things.
    – Vidro3
    Commented Nov 13, 2014 at 19:46
  • 2
    As opposed to an "8 foot-long bridge", which is a bridge composed of 8 foot-long sandwiches. Commented Nov 13, 2014 at 21:00

2 Answers 2


In the United States, most style guides that I have encountered recommend including the second hyphen in situations such as "8-foot-long bridge." Here is how some guides frame their advice. From The Associated Press Stylebook (2002):

dimensions Use figures and spell out inches, feet, yards, etc., to indicate depth, height, length, and width. Hyphenate adjectival forms before nouns.

[Relevant examples:] the 5-foot-6-inch man, the 9-by-12 rug

From The New York Times Manual of Style and Usage (1999):

long(-), (-)long ... As a suffix, long forms a solid compound when it attaches to a one-syllable word ending in a consonant. The compound is hyphenated if the suffix directly follows a vowel or a word of more than one syllable: daylong, decade-long, hourlong, minute-long, mile-long, monthlong, second-long, weeklong, yearlong. Do not attach -long to a plural: instead of weekslong delay, write a delay of weeks.

Shorten expressions like two-hour-long meeting. Two-hour meeting says it all.

From The Chicago Manual of Style, fifteenth edition (2003):

7.90 Overview. ... number, spelled out, + noun: a hundred-meter race, a 250-page book, a fifty-year project, a three-inch-high statuette, it's three inches high, five- to ten-minute intervals. (Hyphenated before a noun, otherwise open. Note the space after the first number in the last example.)

From Bryan Garner, Garner's Modern American Usage (2003):

PHRASAL ADJECTIVES. A. General Rule. When a phrase functions as an adjective preceding the noun it modifies—an increasingly frequent phenomenon in 2oth- and 21st-century English—the phrase should ordinarily be hyphenated. Hence, the soup is burning hot becomes the burning-hot soup; the child is six years old becomes the six-year-old child. Most professional writers know this; most nonprofessionals don't.


PUNCTUATION. ... J. Hyphen [-]. ... Here's the rule: if two or more consecutive words make sense only when understood together as an adjective modifying a noun that follows, those words (excluding the noun) should be hyphenated.

Since we're talking about punctuation style here, there is no single objectively correct way to handle the hyphenation of compound adjectives; but as a matter of convention, the style guideline that yields "8-foot-long bridge" is considerably more firmly established in U.S. publishing than the one that yields " 8-foot long bridge."


According to the AP Stylebook, hyphens are not a standardized form of grammar. They are optional, as is their method of use. The Stylebook states "It is optional in most cases, a matter of taste, judgment, and style sense." If the phrase would be clearer with a different use of hyphen, then that use would be preferred.

Is this phrase clearer as a result? 8-foot-long bridge clearly means the length of the bridge. An 8-foot long bridge could mean a long bridge which has an 8-foot feature of some sort.

Up to the writer, I think.

  • Hyphens are orthographic artifacts. They have nothing whatsoever to do with grammar, which is about speech.
    – tchrist
    Commented Nov 13, 2014 at 21:04
  • @tchrist. Are you suggesting that grammar is concerned only with speech with the written word? If you am, I do be disagreeing on you.
    – tunny
    Commented Nov 13, 2014 at 21:12
  • @tunny That’s right: grammar has nothing to do with orthography. Illiterates have grammar.
    – tchrist
    Commented Nov 13, 2014 at 21:12
  • Well, if it is not grammar, then my statement is still correct. It is NOT a standardized form of grammar.
    – bsdarby
    Commented Nov 13, 2014 at 21:24
  • @tchrist The second sentence in my previous comment had nothing to do with orthography. The spelling was fine, but the grammar was not perfect. Should we ignore that because I wrote it rather than said it? I believe that grammar is as much part of the language expressed in the written as in the spoken form. Do you agree? As a secondary point, I think that spelling and punctuation (and pronunciation) are not completely apart from grammar, as I believe is shown by the written and spoken versions of "The dog chased it's tail. It shouldn't of done that"
    – tunny
    Commented Nov 13, 2014 at 21:29

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