What's the difference between these two phrases?

  • their systems’ security posture
  • their systems security posture

Is there any difference in the meaning? If not, when we use either of them?

  • One's system is plural, possessive and grammatical, the other not.
    – mplungjan
    Commented Nov 10, 2014 at 15:55
  • @mplungjan: I disagree. They're both grammatical. One is possessive, the other could be said to use a "plural attributive noun". You might think such plural usage is at the very least "a bit unusual", but I don't think it's inherently "incorrect". Highly topical, actually, since tomorrow is Veterans Day - which is invariably pluralised, with no apostrophe. Commented Nov 10, 2014 at 16:05
  • If the second had been their system's security posture it would have been singular and possessive. I do not see their systems security posture being correct in any way. The veterans in Veterans Day is an attributive adjective and not possessive or it should have been Veterans' Day
    – mplungjan
    Commented Nov 10, 2014 at 16:13
  • Hmm, reading the other answer, I will have to retract half my comment. "systems security posture" could be the title of a posture. I would expect it to be "system security posture" though
    – mplungjan
    Commented Nov 10, 2014 at 16:22

2 Answers 2


The phrase "[...] their systems' security posture [...]" uses a possessive form to show that security posture quality belongs to the systems.

The phrase "[...] their systems security posture [...]" is using "systems security posture" as a noun phrase, as though "systems security posture" is a thing. This might be a matter of jargon, but I've not heard that expression before. Still, it almost certainly means the exact same thing as the first phrase.

  • The second one is just an example which I made to clarify the difference, because i can't understand when to use the possessive form. e.g. "infrastructures' defense systems" or "infrastructures defense systems"?
    – vahid3561
    Commented Nov 10, 2014 at 16:14
  • I see. The possessive form is used to show that the noun that follows belongs to the person(s) whose name takes the possessive form. For example, If you want to talk about a baseball bat that belongs to John, you would say, "John's baseball bat [...]". If you didn't use the possessive form (no apostrophe), you'd be using a plural as "Johns", which means two or more Johns. :) Use the possessive form with apostrophe when you want to show a thing belongs to someone or something. Use the plural form when you want to show there are two or more of the thing.
    – R Mac
    Commented Nov 10, 2014 at 16:19
  • In your example "John" is a person and it's clear that plural "Johns" doesn't make sense, but in my example "infrastructures" is plural in both forms, but I cant find whether it should be in possessive form or not
    – vahid3561
    Commented Nov 10, 2014 at 16:29
  • 1
    Let's take a simple noun, like "dog". If the dog has a toy, it's the "dog's toy". That's easy enough. If three dogs all share a toy, it's "the dogs' toy". That structure with the apostrophe after the "s" usually indicates plural possessive. In the case of your above example, then, the "s" + apostrophe on "systems'" indicates plural possessive, meaning the thing that follows belongs to two or more systems. Make sense?
    – R Mac
    Commented Nov 10, 2014 at 16:34
  • I know how to use possessive form and its meaning. If we delete the "posture" then which one is correct? systems security or systems' security?
    – vahid3561
    Commented Nov 10, 2014 at 17:00

their systems’ security posture

The security posture of their systems.

their systems security posture

The 'systems security' posture of them (whoever 'they' are).

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