5. Plurals and Possessives

5.1 Names

Form plurals of words or family names that end in s by adding es.

The Jameses live in West Durham.

Form possessives of words or proper names that end with s, x, es, and z as follows.

Burns’s poems (singular noun ending with s)
Marx’s theories (singular noun ending with x)
Savitz’s holdings (singular noun ending with z)
The Jameses’ house (plural noun ending with es)

5.2 Plurals

Most plurals can be formed by adding a final s, including years and initials.

the early 1980s
several YMCAs
CODs and IOUs
in twos and threes

However, in rare cases, an apostrophe is needed when forming a plural in order to avoid confusion.

M.A.’s and Ph.D.’s
S’s, A’s, and I’s

alumni (not alumnuses)
appendixes (preferred to appendices)
curricula (not curriculums)
data (not datums)
indexes (preferred to indices)
media (not mediums)
memoranda (not memorandums)
millennia (not millenniums)
syllabi (not syllabuses)
symposia (not symposiums)

5.4 Common errors involving possessives

Proper names and nouns form the possessive with the addition of an apostrophe and an s. However, possessive pronouns do not require the apostrophe.

The car’s tires need to be replaced. (noun)
Their anniversary is in March. (possessive pronoun)
The committee reviewed its agenda. (possessive pronoun)

It’s is the contraction of it and is and should not be confused with the possessive pronoun its (which does not use the apostrophe).

It’s time to go home. (contraction of it is)
The car lost its hubcap. (possessive pronoun)

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