Regular Plurals
Most English nouns form the plural by adding -s or -es.
| Rule | Singular | Plural |
|---|---|---|
| Most nouns → add -s | book | books |
| Ending in -s, -ss, -sh, -ch, -x, -z → add -es | bus, watch, box | buses, watches, boxes |
| Ending in consonant + -y → change y to -ies | city, baby | cities, babies |
| Ending in vowel + -y → add -s | day, key | days, keys |
| Ending in -f or -fe → change to -ves (usually) | leaf, knife | leaves, knives |
| Ending in -o (some) → add -es | tomato, potato | tomatoes, potatoes |
| Ending in -o (music/foreign) → add -s | piano, photo | pianos, photos |
Irregular Plurals
Some nouns change their internal vowel or use a completely different form:
| Singular | Plural |
|---|---|
| man | men |
| woman | women |
| child | children |
| foot | feet |
| tooth | teeth |
| goose | geese |
| mouse | mice |
| person | people |
| ox | oxen |
Zero-Change Plurals
Some nouns have the same form in singular and plural:
sheep, deer, fish, series, species, aircraft, spacecraft
Latin/Greek Origin Plurals
| Singular | Plural |
|---|---|
| criterion | criteria |
| phenomenon | phenomena |
| cactus | cacti / cactuses |
| focus | foci / focuses |
| datum | data |
Real world: shopping list and menu
Please buy: two loaves of bread, three boxes of cereal, a bag of potatoes, and some tomatoes. Today's menu: grilled fish, roasted vegetables, and knives and forks on every table.
Real world: school report / notice
All children must submit their essays by Friday. Women and men in the parent teams should contact the school office. The mice in the science lab will be cared for by the staff.
Practice Problems
Write the plural of: box
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Write the plural of: city
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Write the plural of: child
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Write the plural of: leaf
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Write the plural of: sheep