What is the possessive of a noun ending in ‑s? Are these both right, or is the second one wrong?

  1. the boys' books

  2. the boss' car


Your example sentences confuse two different problems.

For nouns that are plural (such as "boys"), the possessive is formed in writing by adding an apostrophe after the plural -s. This is pronounced the same as the plural and the singular possessive:

The boys' books [boys' sounds like boys]

For singular nouns that end in -s, the possessive is formed by adding -'s, just as with other nouns. This is pronounced as if the spelling were es:

The boss's car [boss's sounds like bosses]

There is a partial exception for proper names that end in s. These names sometimes form their possessive by simply adding an apostrophe, and without changing their pronunciation:

Confucius' sayings

Jesus' teachings

However, this doesn't apply if the name ends with a letter other than s, even if it's pronounced with an s. These names form their possessive as normal:

Marx's theories

In the opposite case of a name which ends in a silent s, the possessive is usually formed by adding an apostrophe in writing, but the apostrophe causes the silent s to be pronounced:

Camus' novels [the final -s in Camus is not silent here]

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    +1, I hadn't thought about the implications of the proper name exception when used with a silent final s. – cori Aug 16 '10 at 22:08
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    +1, but I'll note that there exist style guides which follow the following simplistic rule: if a singular noun ends with an s, just add “'s”, regardless of whether it's a proper noun or how it's pronounced. I like the simplicity of this rule. – ShreevatsaR Aug 16 '10 at 22:32
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    Do you have a source on this with proper names not needing an extra s? I am fairly certain it should still be Confucius's sayings, Jesus's teachings, and Camus's novels, with the first s still silent in the last case. – StrixVaria Aug 19 '10 at 16:13
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    @FumbleFingers But "mistresses" is already plural and wouldn't get the extra s after the apostrophe anyway. – StrixVaria May 26 '11 at 1:23
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    Do you have any authoritative references? I'm not asking because I don't believe you. I'm asking because when the question comes up I can't say "because some guy on the internet said so", not even if said guy got 60 upvotes. – Szabolcs Feb 26 '15 at 18:08

On singular nouns that end with an "s" or "z" sound, Wikipedia has a say. According to the article, there is no hard and fast rule on this one and different "authorities" prefer different styles.

See also St. James's park and St. James' park.


On the use of so-called 'zero genitive', marked by a simple apostrophe in spelling ('), and the 's possessive with nouns ending with an s, Quirk, Greenbaum, Leech and Svartvik specify in A Comprehensive grammar of the English Language (pp. 320 & 321) that:

In addition to its normal use with regular plurals such as boys', the 'zero genitive' is used to avoid repetitive or awkward combinations of sounds in the following cases:

(i) with Greek names of more than one syllable that end in -s, as in:

Euripides' /di:z/ plays, Xerxes' army, Socrates' wife

(ii) with many other names ending in /z/, where in speech zero is a variant of the regular /ɪz/ genitive. There is vacillation both in the pronunciation and in the spelling of these names, but most commonly the pronunciation is /ɪz/, and the spelling is an apostrophe only. (In the following examples, the minority form is given in parentheses.)


Burns' (Burns's) poem

Dickens' (Dickens's) novels

Jones' (Jones's) car


/ˈbɜ:nzɪz (bɜ:nz)/

/ˈdɪkɪnzɪz (ˈdɪkɪnz)/

/ˈdʒəunzɪz (dʒəunz)/

Names ending in other sibilants than /z/ have the regular /ɪz/ genitive: Ross's /ˈrɒsɪz/ theories. However, Jesus and Moses normally have the zero form of the spoken genitive, /ˈdʒi:zəs/ and /ˈməuzɪz/, and are written Jesus' and Moses' (as well as Jesus's and Moses's).

(iii) with fixed expression of the form for . . . sake, as in for goddness' sake, for conscience' sake, where the noun ends in /s/.

Boss ends in a sibilant, /s/, other than /z/, and becomes boss's in the possessive. So we have the boss's car.

  • What corpora did Quirk et al use? These Google Ngrams seem to strongly suggest that Burns' is the minority form. If I'm reading them correctly. / tchrist has answered elsewhere that 's and the /ɪz/ pronunciation are almost always twinned. – Edwin Ashworth Nov 28 '19 at 15:54
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    @EdwinAshworth The list of abbreviations and symbols has SEU which stands for Survey of English Usage (en.wikipedia.org/wiki/Survey_of_English_Usage) founded by Quirk himself in the late fifties at UCL. I agree that the 's forms form Burns, Dickens, Wells and similar names feel intuitively more widespread. Perhaps Quirk et al.'s remark is more prescriptive than descriptive. – grandtout Nov 28 '19 at 18:38
  • Hmm, he's/they're usually pretty good. // I came across something giving a rule-of-thumb ('Truss', I think) that usages 'concerning antiquities' tended not to add the second s while more modern examples did (or vice versa). I wondered if this licensed Athens' glory days were millenia ago; Athens's more recent history may not be so well known. – Edwin Ashworth Nov 28 '19 at 19:14
  • @EdwinAshworth According to Longman Pronunciation Dictionary, "With proper names ending in a sibilant, usage varies. Usually, the possessive is pronounced regularly, though the spelling may vary: Jones’ , Jones’s dʒoʊnzəz. Less commonly, the possessive ending is unpronounced (dʒoʊnz), but the corresponding spelling is then Jones’ " – GJC Jul 23 '20 at 17:02
  • @GJC Do they mention what research they've carried out? Certainly ACGEL (1985) must be out of date on this now. – Edwin Ashworth Jul 23 '20 at 18:13

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