Over the years there have been postings to AUE that were based upon the misconception that
the genitive case always indicates possession. This fallacy leads to people
saying things like 'It can't be right to say "the room's furnishings" because a room
can't possess something.'
The genitive case is in fact used for several things besides possession. Bergen and
Cornelia Evans, in A Dictionary of Contemporary American Usage, discuss seven
Classifying or descriptive genitive ("the room's furnishings")
Possessive genitive ("Irene's coat")
Subjective and objective genitive ("God's creation")
Genitive of purpose ("He has written many children's books.")
Measures and other adverbial genitives ("At one time the
genitive form of certain words could be used as an adverb.
Most of our adverbs that end in an 's' (or 'z') sound,
such as "nowadays," "since," "sometimes," "upwards," are
survivals from this period.)
Survivals of "an old genitive of source" ("hen's eggs")
Partitive and appositive genitives (don't exist in English,
but we express them with an "of" phrase, as in "some of us,"
"the state of Ohio," "the title of president")
(The Evanses give a detailed discussion of each type; I've only hinted
at their discussions, mostly by giving a few examples.)
Merriam-Webster's Dictionary of English Usage says, in part:
Bishop Lowth in 1762 used the word possessive in place of the older term genitive; so then did other 18th-century
grammarians, and many grammarians since have used it. This change in terminology has led to a few minor usage problems
based on the erroneous supposition that the only function of the genitive is to show possession. [...] Fries found that
the possessive genitive was the most common, but that it accounted for only 40-percent of all genitives.
They discuss a number of uses of the genitive and give examples of
each. Under 'descriptive genitive or classifying genitive', with
the comment 'Fries adds the genitive of measure to this', they list:
the room's furnishings
the airplane's speed
the building's foundation
one day's leave
a dollar's worth
a year's wages
the Eighty Years' War
A comment in MWDEU concerns the rephrasing of the
genitive with apostrophe to a structure with a prepositional phrase,
'the airplane's speed' => 'the speed of the airplane'.
They point out that in what one grammarian (Evans) has
called the genitive of purpose the prepositional phrase must use the
preposition 'for' rather than 'of', as in:
'men's shirts' => 'shirts for men', and
'a girls' school' => 'a school for girls'.
Mark Israel's AUE FAQ doesn't cover the genitive-equals-possessive
fallacy per se, but he does skirt the perimeter of it with:
The Latin plural of "curriculum vitae" is "curricula vitae".
[ . . . ]
This is a feature of the Latin genitive of content, which
differs in this regard from the more common Latin genitive
A classic story in linguistics lore tells of the grammarian who tried
to classify all of the ways the genitive can be used. He eventually
threw up his hands and said that the genitive is the case that shows
any relationship between two substantives.