7.56 Possession

The primary use of the apostrophe is to indicate possession. A word which does not end in a sibilant (s or z sound) forms the possessive by the addition of ’s:

• a dog’s breakfast
• Toronto’s CN Tower

To form the possessive of French words ending in a non-sibilant s or x, add an ’s:

• Duplessis’s cabinet
• Malraux’s art

Note that it is the pronunciation, not the spelling, which determines the possessive form. The word conscience ends in a sibilant; Illinois does not. Plural forms which do not end in a sibilant are no exception to the general rule:

• women’s
• children’s

Plurals ending in a sibilant take only the apostrophe:

• the ministers’ responsibilities
• developing countries’ needs

Regarding the appropriate form for singular words that end in a sibilant, pronunciation is again the determining factor. If it would be natural to pronounce an extra s, add ’s; if an additional s would be difficult to pronounce, add only an apostrophe:

• Joyce’s Ulysses
• Ulysses’ wanderings
• Brussels’ bureaucrats
• the boss’s office

Since awkwardness of pronunciation is the basic criterion, the decision to add or omit a possessive s ultimately depends on the writer’s own sensitivities. One option is to rephrase:

• the tourist industry of Mauritius
• the ramblings of Joyce’s Ulysses

rather than

• Mauritius’ tourist industry
• Joyce’s Ulysses’ ramblings

7.57 Inanimate possessors

With inanimate "possessors," especially abstract concepts, the apostrophe is generally not used to denote possession. Use an "of" construction instead:

• the incidence of conjugal violence
• the priority of tourism

not

• conjugal violence’s incidence
• tourism’s priority

However, certain expressions of time and measurement do take the apostrophe:

• a month’s vacation
• ten dollars’ worth

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