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Word choice & usage · Topic 9 of 17

Plurals, Possessives & Apostrophes

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Grammar · plurals & apostrophes

Plurals, Possessives & Apostrophes

Most plurals add -s or -es; singular nouns take 's, plurals ending in s take only ', and plain plurals never take an apostrophe.

01 · PluralsAdd -es after s, sh, ch, x, z
02 · Possessivesnurse's (one) · nurses' (more than one)
03 · The trapPlurals never take an apostrophe
01

The rules

Add -s; add -es after s, sh, ch, x, z: chart → charts, box → boxes, dish → dishes must know
Consonant + y → -ies; vowel + y → -s: baby → babies, key → keys must know
Singular + 's · plural in -s + ' · other plurals + 's: nurse's, nurses', women's must know
Some -f/-fe nouns → -ves: wife → wives, loaf → loaves · but roof → roofs
Some -o nouns add -es: potato → potatoes · but radio → radios
Compounds pluralize the main word: brother-in-law → brothers-in-law
Joint: Kim and Lee's car · separate: Kim's and Lee's cars
A contraction's apostrophe marks the missing letters: do not → don't, I am → I'm
Singular noun ending in s usually adds 's: the boss's desk, the class's hours
02

Possessives

✗ The two doctor's offices are closed → ✓ The two doctors' offices are closed
✗ The babys' blankets were washed → ✓ The babies' blankets were washed
03

One owner or more than one?

Commonly confused
Singular possessivePlural possessive
Ruleadd 'splural ends in s: add ' · other plurals: add 's
Regular nounthe nurse's badgethe nurses' lounge
Irregular nounthe child's coatthe children's coats
Noun ending in sthe boss's officethe bosses' offices
04

Common mistakes

No apostrophe in a plain plural — ✗ three chart's → ✓ three charts must know
Form the plural, then add 's — ✗ childrens' clinic → ✓ children's clinic
05

Also know

Irregular plurals: child → children, tooth → teeth, foot → feet, mouse → mice
Same word for one or many: one sheep, two sheep · one deer, ten deer
-is → -es, -on → -a: diagnosis → diagnoses, crisis → crises, criterion → criteria
-us → -i, -um → -a, -a → -ae: nucleus → nuclei, bacterium → bacteria, vertebra → vertebrae
06

More detail

Show 4 more facts
Plural -ies + apostrophe: three companies' policies (✗ three company's policies)
Names ending in s, ch, z add -es: the Joneses' dog, the Birches' house
Time and money can be possessive: a week's pay, three days' notice
Plural lowercase letters keep an apostrophe: dot your i's
Pearl

Make the plural first, then decide where the apostrophe goes.

Sources · Cambridge English Grammar Today — Nouns: form (forming the plural of nouns) · GrammarBook.com — Apostrophes (Rules 1–11) · OpenStax Writing Guide with Handbook — Handbook (H9 Punctuation: Apostrophes) · Cambridge Dictionary — criterion (plural criteria) · Cambridge Dictionary — diagnosis (plural diagnoses) · Cambridge Dictionary — nucleus (plural nuclei) · Cambridge Dictionary — vertebra (plural vertebrae) · Cambridge Dictionary — bacterium (plural bacteria) · LibreTexts (San Jacinto College ESOL Grammar) — Regular Plural Nouns · Union Test Prep — HESI A2 Grammar study guide p. 4 (apostrophes: possession, contractions, misuse) · TSTC Library — HESI A2 guide (Grammar: possessives; quotation marks and apostrophes) · Built from the verified NurseSavvy HESI A2 fact map (facts reviewed 2026-10-16). HESI is a trademark of Elsevier; NurseSavvy is not affiliated with Elsevier.

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