I was just posting a question to the Homebrewing StackExchange, and I found myself pondering the proper way to express my sentiment.

I first wrote "an hour's rest", but upon review, I deemed the apostrophe extraneous. What is the proper way to form this phrase? I can't make a case for the word 'hour' being plural or possessive, so I'm beginning to think the whole letter 's' is unnecessary.

Thoughts, anyone?

  • 1
    No, the s is not unnecessary -- "an hour's rest" by itself sounds perfectly alright. Helps if you post the complete sentence to know about "for the word 'hour' being plural or possessive," though.
    – Kris
    Commented Jan 12, 2012 at 6:40
  • Related question: english.stackexchange.com/questions/29220/…
    – Golden Cuy
    Commented Jan 15, 2013 at 11:40

4 Answers 4


This is what the Chicago Manual of Style terms an "idiomatic shorthand form of an of-phrase:"

an hour's delay is equivalent to a delay of one hour, or a one-hour delay

So: an hour's rest can be phrased as a one-hour rest. (I find a rest of one hour a bit stilted...)

Edit: As noted in my comment, in this idiom, delay or rest "belongs" to hour (it's of one hour), so it's "an hour's delay."

  • So the apostrophe is appropriate? Does the manual give any explanation as to why?
    – Colin
    Commented Jan 12, 2012 at 6:49
  • 4
    It's an example of a genitive. CMoS describes the genitive as having seven different functions, but you can loosely describe it as possessive. In this idiom, the delay "belongs" to the hour (it's of one hour), so it's "an hour's delay."
    – Gnawme
    Commented Jan 12, 2012 at 6:56
  • I wonder if this can be described as an example of the "pathetic fallacy", a rhetorical device, in this case making the hour itself rest instead of the person or thing which is being given a rest?
    – MetaEd
    Commented Jan 12, 2012 at 15:35
  • @MetaEd This article has a nice explanation of the genitive, and how it's not always possessive.
    – Gnawme
    Commented Jan 12, 2012 at 18:44

I've always seen it with the apostrophe. Without would look goofy. Wikipedia has an explanation as to why (not that it's a standard grammar reference but I believe in this case it's correct):

An apostrophe is used in time and money references, among others, in constructions such as one hour's respite, two weeks' holiday, a dollar's worth, five pounds' worth, one mile's drive from here. This is like an ordinary possessive use. For example, one hour's respite means a respite of one hour (exactly as the cat's whiskers means the whiskers of the cat). Exceptions are accounted for in the same way: three months pregnant (in modern usage, we do not say pregnant of three months, nor one month(')s pregnant).


No one is going to object if you write an hour's rest. It's often misleading to think of the apostrophe s as expressing possession, at least in the sense in which it is commonly understood. It makes more sense to think of it as a remnant of the genitive case, capable of expressing a range of meanings. However, there are signs that, in such cases as this, the apostrophe mark itself is disappearing and, as far as I'm concerned, good riddance.


Yep, the delay belongs to the hour. Kinda weird when you think about an hour owning something, but it's the noun-adjectival link which forces phrases like this into the rule.

Besides, think of it like this. How can you ever have "an hours rest'? One hours? The rest cannot be modified by "an hours" because it's a glaring grammatical error! It is modified by "an hour", and so that's why the apostrophe is needed.

  • But various variants of nine days wonder (including the no-apostrophe version) are licensed by some authorities. There are writers guilds as well as writers' guilds, and more working mens clubs than working men's clubs. And travellers cheques and dogs homes. and Waterstones. The 'apostrophe where no true ownership is asserted' is often acceptably dropped nowadays. Commented Sep 10, 2020 at 15:09

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