When the singular noun ends in consonant + y, change the y to i before adding –es to form the plurals.

Singular – plural

Baby – babies

Lady – ladies

Kitty – kitties

Party – parties

Berry – berries

Ferry – ferries

If the singular noun ends in vowel + y, form the plural by adding -s.

Singular – plural

Day – days

Boy – boys

Donkey – donkeys

Monkey – monkeys

Guy – guys

Toy – toys

If the singular noun ends in sh, ch, s, x or z, form the plural by adding –es to the singular.

Singular – plural

Fox – foxes

Box – boxes

Church – churches

Bus – buses

Clash – clashes

Some singular nouns ending in –o, have plurals ending in –es

Singular – plural

Potato – potatoes

Tomato – tomatoes

Hero – heroes

Zero – zeroes

Negro – negroes

Singular nouns ending in vowel + o have plural nouns ending in –s.

Singular – plural

Zoo – zoos

Photo – photos

Kilo – kilos

Commando – commandos

Logo – logos

In some cases, the plural can end in –s or –es

Buffalo – buffaloes / buffalos

Mosquito – mosquitoes / mosquitos

Volcano – volcanoes / volcanos

Irregular and special plurals

Some singular nouns ending in –f or –fe have plurals ending in –ves

Calf – calves

Elf – elves

Half – halves

Knife – knives

Leaf – leaves

Life – lives

Loaf – loaves

Self – selves

Shelf – shelves

Thief – thieves

Wife – wives

Wolf – wolves

Other irregular plurals

Some singular nouns form their plurals irregularly.

Examples are given below.

Child – children

Foot – feet

Ox – oxen

Goose – geese

Louse – lice

Man – men

Woman – women

Tooth – teeth

Person – people

Some nouns have the same form in the singular and the plural.

Examples are given below:

Means – means

Headquarters – headquarters

Crossroads – crossroads

Series – series

Species – species

Foreign plurals

Some words coming from foreign languages have special plurals.

Singular – plural

Analysis – analyses

Appendix – appendices

Bacterium – bacteria

Basis – bases

Cactus – cacti

Criterion – criteria

Diagnosis – diagnoses

Formula – formulae

Fungus – fungi

Medium – media

Nucleus – nuclei

Phenomenon – phenomena

Radius – radii

Stimulus – stimuli

Vertebra – vertebrae

Plurals of compound nouns

Singular / Plural

Passer-by / passers-by

Runner-up / runners-up

Son-in-law / sons-in-law

Mother-in-law / Mothers-in-law

Daughter-in-law / Daughters-in-law

Step-son / step-sons

Maid-servant / maid-servants