I gave a quick answer to part of this question which had not been covered by previous answers, trying to clarify the reason you would say time of decoding but not decoding’s time. I said it was ’s usually indicates possession, but of course there were several counterexamples that would have occurred to me after a moment’s consideration, and these where helpfully supplied:

  • Britain’s climate
  • two days’ time
  • a day’s work
  • the sun’s rays

I am still of a mind to say that possession of some sort is what allows the ’s. Even though the sun does not have title to its rays, they do belong to the sun. Now, at the risk of duplicating the original question and/or being pigheaded, I am curious as to why time of decoding but not decoding’s time is correct, if not for the reason I gave.

  • See this question.
    – tchrist
    Commented Aug 28, 2012 at 0:54
  • 3
    There is a difference between time of decoding and decoding time. The decoding time is the time that it took to perform the decoding. The time of decoding is the time at which something was decoded. So if you started working on something at 1pm, the decoding time might be two hours, and the time of decoding might be 3pm. Commented Jan 15, 2013 at 17:40
  • We also see decoding as a verbal activity even when it's used nominally, so the genitive 's marker doesn't fit. I would say that the preposition of is like a cast( ), wresting the word into nominal. The genitive clitic would be like a backwards looking parse.
    – TimR
    Commented Aug 25, 2023 at 21:57

6 Answers 6


In The New Fowler's Modern English Usage, the late Burchfield offered a guide to the use of possessive s and of with inanimate nouns. It is the most comprehensive and well founded stylistic advice I could find on the subject. He had worked on the Oxford English Dictionary and knew a lot about language and style. A summary:

A noun that is possessive or preceded by of modifies another noun: in my mother's bed / the bed of my mother, bed is the head noun, modified by my mother's / of my mother. Usually, inanimate modifier nouns should be preceded by "of"; but there are many possible exceptions, some of which are given here.

  1. An important exception is the so called thematic genitive: if a noun has gained strong topical value, because it is central in a discussion or description, it may get the possessive s.

    • That is a beautiful teapot. And those teacups must be Meissen. Notice the teapot's ornate lid and slender figure.
  2. Nouns defining a specific quantity of time or space, as used in many semi-fixed expressions, may get the possessive s.

    • A day's work

    • A hair's breadth

  3. Words modifying the word sake.

    • For heaven's sake
  4. Words modifying the word edge.

    • The cliff's edge
  5. Words for a ship or boat (and probably other vehicles; these could be classified as thematic genitives, or as cases of personification: see 1 and 7, and compare the use of she for vessels).

    • The ship's crew

    • The plane's left wing

    • The train's front car

  6. Other fixed expressions, usually monosyllabic nouns.

    • Out of harm's way

    • The sun's rays

  7. A personified inanimate noun; i.e. whenever a thing is invested with a will or the ability to act (this exception is an addition of my own). This is related to the use of she for certain countries and vehicles.

    • Britain's might

    • Fear's claws

The pronoun its is by definition reserved for inanimate objects and hence universally possible. The use of whose with inanimate objects appears to be much less restricted than the possessive s, perhaps because relative clauses always express elaboration on a central theme (thematic genitive). This is not surprising, since the essence of a pronoun is that it refers to existing information, i.e. it is highly topical.

The relevant passages from Burchfield:

For inanimate nouns, and particularly for such nouns consisting of more than one syllable, the of-construction is customary (e.g. the roof of the church, not the church's roof: the resolution of the problem, not the problem's resolution).


There is general agreement that the non-personal genitive is frequently used with nouns of time (e.g. the day's routine, an hour's drive) and space (e.g. the journey's end, a stone's throw, at arm's length). It is also often used before sake (e.g. for pity's sake, for old times' sake), and in a number of fixed expressions (e.g. at death's door, out of harm's way, in his mind's eye). Jespersen noted the prevalence of 's genitives before the word edge (the cliff's edge, the water's edge, the pavement's edge, etc.). He also noted that ship, boat, and vessel tend to turn up with an 's genitive when we might expect of (the ship's provisions, the boat's gangway, etc.).

In 1988 Noel Osselton demonstrated that the somewhat unexpected types the soil's productivity and the painting's disappearance (as well as others) represent a legitimate class of what he called thematic genitives. When a noun that cannot 'possess' is of central interest in a particular context, it tends to acquire the power to 'possess', and is therefore expressed as an 's genitive.

One major genitival area remains virtually untransformable into 's genitives. Only the of-construction is appropriate for partitive genitives: e.g. a glass of water cannot be re-expressed as a water's glass, and try converting a dose of salts.

I tested these rules against my files and found them largely in accord with my own evidence. The great majority of 's genitives still occur with animate nouns. ... It does seem from the evidence available to me that the 's genitive for inanimate nouns is commoner now than it was a century ago[.]

  • 4
    I appreciate that you have a source, but this advice is simultaneously so complicated and so vague ("other fixed expressions," personifications, etc) that it strikes me as somewhere close to useless, and I frankly expect that most of these prescriptions cannot be supported but by opinion. Commented Aug 28, 2012 at 2:03
  • 11
    @EvanHarper: Then what do you expect, a mathematical formula? It's a language. This is as good as it gets. Commented Aug 28, 2012 at 13:13
  • 5
    @EvanHarper: I'm sorry to have to say this, but even using the word "fact" is inappropriate here. This isn't about simple things with easy-to-state internal structures. As to the examples you have provided, let me address them. The issue with the cliff's edge is not that it should be compulsory, but that it is at all possible and so used even when it is not a thematic genitive, as opposed to most inanimate nouns. That applies to the sake of humanity and the edge of sanity as well. Your other two examples can very well be thematic genitives. Further note that these stylistic rules are ... Commented Aug 28, 2012 at 20:43
  • 5
    1. not meant to be hard and fast, even for good writers, and 2. no doubt even more often ignored by bad writers. Remember, this is stylistic advice, even though it is to some extent based on usage. Lastly, you cannot research anything more complicated than the most basic linguistic phenomena conclusively through automated computer searches, especially not this thematic genitive. Commented Aug 28, 2012 at 20:47
  • 3
    It's worth noting that the KJV, and Tyndale's English bible before it, avoided either the old-fashioned his or the more modern its as the neuter genitive pronoun (its is now the only word we would use here now, but it was a stuffy vs slangy language controversy of the time, and Tyndale didn't want to back the wrong horse). This led to a heavy use of of and thereof that in turn influenced many people's ideas of what "good English", "formal English" and/or "posh English" should sound like. It leads both to some of Fowler's advice here, and much lawyer-speak.
    – Jon Hanna
    Commented Jan 15, 2013 at 14:12

There are actually three possible constructions to express what you want to (using decoding + time): decoding time, time of decoding, and decoding's time.

Yes, that's right: I'm going out on a limb here and saying there are cases where you might use "decoding's time" — as odd as that may sound. Let's look at the different meanings (N.B. I am taking the most likely meaning of each, but all could be used in any of the senses):

  1. decoding time — meaning the time it takes to decode something or
  2. time of decoding — meaning the time at which something was or will be decoded
  3. decoding's time — taking the decoding itself as an entity which can have a right time or a wrong time, or some other qualitative measure of timeliness, and judging whether it was appropriate in that respect.


Yes, the decoding could have been done upon receipt of the message, but it wasn't the decoding's time. That would come later.

This could be said in other ways, but this way keeps "the decoding" as the subject, without transferring that property to time itself; it also keeps the noun time at the end of the sentence, where it is in an appositive relationship to the sentence that follows. I'm not sure if there is any real benefit to this, but it is a possibility and might serve as a stylistic variant in some cases.


It's true that the Saxon Genitive indicates possession but there is a rule that I think hasn't been mentioned yet (in this question at least), that says that the it is usually adopted with animated objects or better with nouns that refer to living things:

  • Kate's website;
  • Robert's car.

This rule is not absolute and strict, and many people use the possessive also with non-animated objects. But well, this document goes a bit in depth in this matter, although not all of it. This part is related to your question:

Although the analytic and synthetic genitives of English may be interchangeable in a grammatical sense, they are often not so from the viewpoint of stylistics. The genitive formed with apostrophe + s is usually preferred with nouns, both proper and common, that refer to persons and other living things; the analytic genitive formed with of is more usual, at least in formal speech and writing, with inanimate objects.

But this distinction is far from absolute. The synthetic genitive seems perfectly proper in such phrases as the ship’s cargo, our country’s future, and yesterday’s newspaper, and the resistance to expressions such as the liver’s oxygen consumption and Paraguay’s climate is gradually lessening. However, the synthetic genitive is quite impossible in certain circumstances. A single example must suffice. One can say at the back of the room (al fondo del cuarto) but never at the room’s back, which, to a speaker of English, would seem to mean something like “a espaldas del cuarto.

  • I don't know if this totally answers your question but I think there are some info you might use in case you want to keep researching. :)
    – Alenanno
    Commented Jun 18, 2011 at 18:00

English speakers preferentially use the possessive apostrophe when the possessor is a living entity.

When the owner is a living entity, the prepositional phrasing is technically correct, but the possessive apostrophe is highly preferred. Cerberus's answer was well-researched, and illustrated to me that most of the rules/exceptions for inanimate objects are idiomatic and may be specific to a time period. However, I wanted to describe why the possessive apostrophe is useful. It allows the speaker to:

  • Specify the owner without a prepositional phrase.
  • Represent ownership in a natural order.
  • Minimize number of words between the subject and the verb.

Consider the following sentence:

The cat of my sister ate the gerbil of my brother.

It has eleven words, two prepositional phrases, and three words separate the subject and the verb. This is technically correct, but very awkward. Consider this re-write:

My sister's cat ate my brother's gerbil.

The re-write has only seven words, no prepositional phrases, and the verb comes just after the subject. Additionally, the possessive apostrophe allows ownership to be listed from least specific to most specific (i.e. of the many things my sister owns, I'm talking about her cat). That's not a major problem in the context above, where there are two independent statements of ownership, but becomes really important in cases of nested ownership.

Consider the following sentence:

The toy of the cat of my sister is red.

This ten-word sentence is technically correct, but awkward. It has two prepositional phrases, six words between the subject and the verb, and nested ownership (i.e. my sister owns a cat, and that cat 'owns' a toy). Nested ownership isn't bad per-se, but the prepositional phrasing again forces an unnatural order - ownership is listed from most specific (this one toy) to least specific (things my sister owns).

The same idea expressed with two possessive apostrophes:

My sister's cat's toy is red.

This is a lot more concise, in that there are now only six words, no prepositional phrases, and the verb comes just after the subject, so the audience doesn't have to comprehend six qualifying words while remembering that the subject is "toy". It's also more clear in that the nested ownership is listed from the least specific (things my sister owns) to the most specific (this one toy), as you would expect from an outline:

  • Stuff my sister owns
    • shirt
    • car
      • muffler
      • engine
    • cat
      • toy
      • collar
      • water bowl
  • Hey, this is a nice analysis. The only thing I don't understand is this: "Specify a direct object without need for a prepositional phrase". What direct object is that? Commented Apr 16, 2020 at 18:27
  • Yeah, good point - I got that part wrong. For the sentence "The cat of my sister has a red toy", I had interpreted "of my sister" to be a prepositional phrase and "my sister" to be the direct object. But I realize that's not correct; "my sister" is not a direct object, it's the object of the preposition "of".
    – mRotten
    Commented Apr 17, 2020 at 20:00
  • Thanks for your question. I think I've fixed it now.
    – mRotten
    Commented Apr 17, 2020 at 20:03
  • Excellent. It is an object, indeed. Commented Apr 17, 2020 at 20:33

I have been debating this question myself. Both apostrophe+s and of denote possession of some type. The difference seems to be in the type of thing that possesses. For example:

  • Person: 's; Bob's age; Bob's temperature
  • Object: of; the temperature of the water; the age of the fossil
  • Process (something that alters the state of an object or person): of; the time of reaction; the force of impact
  • Quantity: 's; One day's time; One cup's volume

Just a thought.


I am still of a mind to say that possession of some sort is what allows the 's.

As reported from the NOAD, genitive in grammar means "relating to or denoting a case of nouns and pronouns (and words in grammatical agreement with them) indicating possession or close association."

The genitive could also be used for

  • reporting the participation in an action, as agent: he benefited from her mother's love.
  • a reference: the empire's capital.
  • This doesn't really answer the question: why is cooking time not a case of indicating possession or close association in English? I believe it's clear to native speakers that constructions such as water level, flight speed, and computation time do not take the possessive, but what rules would you give to a non-native speaker? Commented Jun 18, 2011 at 16:42
  • The OP says that "possession of some sort is what allows the 's" and my answer is that the genitive is not only for possession, nor possession of some sort.
    – apaderno
    Commented Jun 18, 2011 at 16:58
  • 2
    @PeterShor cooking time, walking stick, teething ring, etc., are examples of {substantive1 + substantive2} which gives substantive2 associated in some way with substantive1. A serious error in grammar was committed in (IIRC) the 18th century when the genitive was dubbed "the possessive." It has little or nothing to do with possession.
    – Greybeard
    Commented Apr 19, 2020 at 21:49

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