Should the apostrophe and the s of genitive Saxon be used after plural forms or words ending with the letter s? For example:

airplanes wings must be defrosted before taking off


airplanes's wings must be defrosted before taking off

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    This is a simple question with a not-so-simple answer. I'm hoping an ELLer will give you a good one, but, in the meantime, you can see what GrammarBook, the Grammar Girl, the CCC grammar pages, the Purdue Owl, and our sister site ELU have to say on the matter. – J.R. Feb 20 '15 at 13:00
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    @J.R.♦: I disagree in the case of OP's specific example. The apostrophe is always written, but the genitive s isn't written unless it's enunciated in the spoken form. Since no-one would pronounce that extra s after possessive plural airplanes, the only credible orthography is "The airplanes' wings must be defrosted". Except in practice most of us would simply use the singular without genitive as an "attributive noun" - as in "Tyre pressures should be checked before a long journey". – FumbleFingers Feb 20 '15 at 13:23
  • I've always been a supporter of 'use one if you pronounce it, don't if you don't. Use a singular if it makes life easier.' too... Chris's house, kids' toys, airplane wings. – gone fishin' again. Feb 20 '15 at 15:18
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    @Tetsujin But that rule isn't particularly helpful for non-native speakers, because you're left with the question of "when do you pronounce it?" which, as you've noted, is almost the same question. (Not precisely the same, since practices differ slightly in speech and writing.) – user230 Feb 20 '15 at 19:18
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    Possible duplicate of How do I pronounce the possessive form of 'case'? – user230 Nov 29 '15 at 2:44

The s-genitive for plural nouns is relatively simple:

1 When the plural does not end in -s you add 's

  • the children's teacher

  • women's football

2 When the plural ends in -s you add only an apostrophe

  • a ladies' hairdresser

  • the teachers' room

More information here:


Normally the s-genitive is not used with things (but it is possible in certain cases).

Normally you use the of-genitive with things. So you would say

  • The wings of areoplanes/airplanes must be defrosted.

Or you use airplane (AmE) as compound element

  • Airplane wings must be defrosted.
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    There is no rule that the s-genitive should not be used with things. It apparently wasn't in the King James Bible, but Shakespeare wrote "It is the show and seal of nature's truth, Where love's strong passion is impress'd in youth", "His wonted sleep under a fresh tree's shade," and "Unpeg the basket on the house's top, Let the birds fly." And I believe that people have been using the 's genitive for things ever since. There is absolutely nothing wrong with "aiplanes' wings". – Peter Shor Feb 21 '15 at 4:59
  • And slightly more recently some English blokes wrote this song a hard day's night... – oerkelens May 16 '16 at 14:53

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