I'm not English hence I don't know how this is called in the first place (that's why the title of this question should be changed) but what I'm referring to is this "s" used in English language to denote something belonging to someone/something or being related to something/someone:

I took my father's coat.

1st question

I wonder what that 's stands for? Does it abbreviate some longer word as it does when it abbreviates is or was (ie. He's tall)?

2nd question

Why do we only use apostrophe when doing the same thing in plural:

I made clients' incomes grow.

I know my examples may be bad/invalid but I would like to know some theory behind this as well as any exceptions to the rule if they existed... I know it's different when you refer to something of the first person. We don't say I's coat but rather My coat. This probably is an exception.

2 Answers 2


This is called the possessive case or the genitive case of a noun. (Possessive is the more common term, but it implies ownership; genitive is more general and implies a relationship.)

In Old English, there were many ways to put a noun into the genitive case, depending on count and gender. But after the 1500s, a noun could only be put into the genitive case with an -es ending. Eventually the e was dropped, leaving us with 's.

Sometime after, the plural genitive was reintroduced with the following convention: Form a plural genitive by adding just an apostrophe only if the normal plural noun ends in s; in all other cases, add -'s as normal. So beavers' and carpenters', but children's and people's. Sometimes you'll also see the convention applied to singular nouns ending with s (e.g., Jesus' ), but this is often discouraged.

Why my instead of I's? My is a possessive adjective and doesn't follow the normal rules.

  • I believe your comment "Sometimes you'll see the convention applied to singular nouns ending with s (e.g., Jesus' ), but this is wrong." is oversimplifying... There's a lot of discussion about this in wikipedia, bottom line is there seems to be little consensus on many variations of this case: en.wikipedia.org/wiki/…
    – Tao
    Commented Dec 23, 2011 at 9:36
  • 1
    Hmm, this page (third question) has a more detailed answer with examples on different practices with respect to that post-apostrophe s: ncsu.edu/ncsu/grammar/Apostro3.html
    – Tao
    Commented Dec 23, 2011 at 9:43
  • It's not really fixed, largely because there are too many rules, they're obviously arbitrary, nobody is clear about the exceptions, they make no sense, and -- most damning -- they don't represent anything in speech. Apostrophe-S genitives are on the way out, already limited to anthropomorphic nouns, and already cliticized to the end of the noun phrase from the noun itself, like The Secretary of State's personal envoy. Nobody cares enough, I think. Commented Dec 23, 2011 at 16:58
  • Perhaps this is obvious to all, but I realized it only recently. Etymologically, "genitive" also implies a specific relationship: that of parent and child (or creator and created). Think "generation." Of course, as a grammatical case, it implies relationship more generically.
    – phoog
    Commented Oct 23, 2012 at 16:23

The apostrophe came into English in the sixteenth century as a device for printers to show that a letter had been omitted. It was not until the eighteenth century that its use to indicate possession became widespread. Before then the possessive s could appear at the end of words without the apostrophe with no indication of whether the words were singular or plural. It’s s because when English was a fully inflected language, s was one of the endings, but not the only one, that indicated the genitive case. The present distinction between ’s and s’ is simply a convention to show singular and plural. It is likely to persist for some time, but there signs that the use of the possessive apostrophe in some cases is diminishing.

  • 1
    ... and that use's of plural apostrophe's in some case's are increasing?
    – phoog
    Commented Jan 4, 2012 at 23:52
  • @phoog: The frequency with which English-language suffixes are appended to things that are not not read as English-language words is much greater than 50 years ago. If I talk about my Acme 430qrs, am I talking about more than one Acme 430qr, or am I talking about just one machine (whose model number ends in qrs)? Most readers would, without difficulty, parse a reference to "Acme 430qr's" as a reference to more than one "Acme 430qr", even if they know nothing of Acme's product line-up. Can the same be said of "Acme 430qrs"? In what way is the latter plural "better"?
    – supercat
    Commented Oct 23, 2012 at 6:23
  • @phoog: I don't know why some people feel compelled to write such silly usages as "apostrophe's" (when "apostrophe" is clearly an English word and is read as such) in complaining about usages like "TLA's" (where TLA isn't pronounced like an English word (i.e. 'tilla') but rather as a sequence of discrete letters "tee el ay"). Normal rules of pronunciation allow TLA's to be instantly verbalized as "tee el ays". By contrast, it's not clear whether TLAs should be "tee el ays", "tee el as", or "tee el ay ess". I know pendants prefer the latter form, but how many people can parse it instantly?
    – supercat
    Commented Oct 23, 2012 at 6:39
  • @supercat In fact, when I learned to write in high school in the early 1980's, I was taught to use an apostrophe to pluralize acronyms and abbreviations (not to mention decades). I first became aware of the trend away from that (e.g., "TLAs") when I was in grad school roughly 10 years later. My comment was a reference to the so-called greengrocer's apostrophe....
    – phoog
    Commented Oct 23, 2012 at 16:07
  • @supercat ... This misuse of apostrophes has always struck me as nothing more than a spelling error. I daresay that one could disambiguate "Acme430qrs" from the context; certainly, in spoken language, one rarely has trouble differentiating (regular) plurals, possessives, and plural posessives (e.g., "bags", "bag's", and "bags'"), which sound the same. I'm curious about your analysis of the role "English word-ness" plays here, which I don't see as particularly relevant. Am I missing something?
    – phoog
    Commented Oct 23, 2012 at 16:09

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