Why do we say the following?

  1. I'll have an hour's wait at the airport
  2. Today's lesson
  3. Yesterday's programme
  4. Two weeks' worth of groceries.

They are not possessive, or are they? Why is the possessive apostrophe used with time expressions and adverbs?

  • 3
    Yes, they are genitive constructions -- more specifically "attributive genitives" where, unlike in most genitives, the genitive noun is an attributive modifier within a nominal.
    – BillJ
    Nov 9, 2017 at 9:00
  • In Bob's example, the construction is a true possessive: Bill has a degree of ownership (whether he quoted or invented the example). But the same construction is also used to show associative rather than possessive relations: the car's front offside wheel (still arguably showing a measure of 'possession', though the car doesn't have ownership rights); Bishop's Stortford; King's Cross/Kings Cross; Lloyd's vs Lloyds; an hour's wait; tomorrow's programme. Nov 9, 2017 at 10:05
  • Related: possession and personification. Nov 9, 2017 at 10:09
  • Many people here will tell you today's lesson is merely associative and if that were true, what difference would it make? Nov 19, 2017 at 19:56

1 Answer 1


As many have said in comments, it is a genitive construction, but not strictly possessive. Compare by rewording, replacing the 's with for/of:

  1. I'll have to wait for an hour at the airport (or a wait of an hour)
  2. The lesson for today
  3. The programme of yesterday
  4. Groceries for two weeks.

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