100 Irregular Plural Nouns in English with Examples

Irregular plural nouns do not follow the normal -s or -es plural rule. For example, child becomes children, man becomes men, and mouse becomes mice. These nouns are common in English, so students and English learners should learn them carefully.

In this guide, you will learn 100 irregular plural nouns in English with examples and sentences. You will also find simple patterns, common mistakes, and easy tips to help you use irregular plurals correctly.

What Are Irregular Plural Nouns?

Irregular plural nouns are nouns that do not become plural by simply adding -s or -es. Instead, they may change spelling, change a vowel, take a special ending, or stay the same.

For example:

• Child changes to children.
• Tooth changes to teeth.
• Sheep stays sheep.
• Cactus changes to cacti.

As a result, irregular plural nouns should be learned as special word forms.

List of 100 Irregular Plural Nouns

This table gives a useful list of irregular plural nouns in English. It includes common daily nouns, same-form plurals, f/fe → ves forms, compound nouns, and a few academic plurals.

No.	Singular Noun	Irregular Plural Noun
1	man	men
2	woman	women
3	child	children
4	person	people
5	tooth	teeth
6	foot	feet
7	mouse	mice
8	goose	geese
9	ox	oxen
10	louse	lice
11	sheep	sheep
12	deer	deer
13	fish	fish
14	trout	trout
15	salmon	salmon
16	bison	bison
17	moose	moose
18	aircraft	aircraft
19	spacecraft	spacecraft
20	species	species
21	series	series
22	means	means
23	headquarters	headquarters
24	leaf	leaves
25	knife	knives
26	wife	wives
27	life	lives
28	wolf	wolves
29	shelf	shelves
30	loaf	loaves
31	calf	calves
32	half	halves
33	thief	thieves
34	elf	elves
35	self	selves
36	scarf	scarves
37	cactus	cacti
38	fungus	fungi
39	nucleus	nuclei
40	radius	radii
41	stimulus	stimuli
42	alumnus	alumni
43	analysis	analyses
44	crisis	crises
45	thesis	theses
46	diagnosis	diagnoses
47	oasis	oases
48	basis	bases
49	parenthesis	parentheses
50	phenomenon	phenomena
51	criterion	criteria
52	bacterium	bacteria
53	curriculum	curricula
54	memorandum	memoranda
55	appendix	appendices
56	index	indices
57	matrix	matrices
58	vertex	vertices
59	axis	axes
60	formula	formulae
61	vertebra	vertebrae
62	antenna	antennae
63	larva	larvae
64	alga	algae
65	genus	genera
66	die	dice
67	penny	pence
68	brother	brethren
69	mother-in-law	mothers-in-law
70	father-in-law	fathers-in-law
71	brother-in-law	brothers-in-law
72	sister-in-law	sisters-in-law
73	son-in-law	sons-in-law
74	daughter-in-law	daughters-in-law
75	passer-by	passers-by
76	runner-up	runners-up
77	attorney general	attorneys general
78	court-martial	courts-martial
79	notary public	notaries public
80	chief of staff	chiefs of staff
81	gentleman	gentlemen
82	fireman	firemen
83	policeman	policemen
84	businesswoman	businesswomen
85	manservant	menservants
86	woman doctor	women doctors
87	man-eater	men-eaters
88	stepchild	stepchildren
89	grandchild	grandchildren
90	schoolchild	schoolchildren
91	toothpick?	toothpicks
92	footnote?	footnotes
93	leafhopper?	leafhoppers
94	mousepad?	mousepads
95	gooseberry?	gooseberries
96	snowman	snowmen
97	workman	workmen
98	sportsman	sportsmen
99	saleswoman	saleswomen
100	chairwoman	chairwomen

Common Irregular Plural Nouns

These are the most useful irregular plural nouns for daily English. Therefore, beginners should learn these first.

Singular	Plural
man	men
woman	women
child	children
person	people
tooth	teeth
foot	feet
mouse	mice
goose	geese
ox	oxen
sheep	sheep
deer	deer
fish	fish

Examples:

• The child is playing.
• The children are playing.
• One mouse ran across the floor.
• Two mice ran across the floor.

Irregular Plural Nouns with Vowel Changes

Some irregular plural nouns change the vowel inside the word. As a result, the plural looks and sounds different from the singular.

Singular	Plural
man	men
woman	women
tooth	teeth
foot	feet
goose	geese
mouse	mice
louse	lice

Examples:

• One tooth is loose.
• Two teeth are loose.
• My foot hurts.
• My feet hurt.

Irregular Plural Nouns That Stay the Same

Some nouns have the same form in singular and plural. Therefore, the sentence context tells us whether the noun means one or more than one.

Singular	Plural
sheep	sheep
deer	deer
fish	fish
trout	trout
salmon	salmon
bison	bison
moose	moose
aircraft	aircraft
spacecraft	spacecraft
species	species
series	series
means	means

Examples:

• I saw one deer near the road.
• I saw three deer near the road.
• This series is interesting.
• These series are interesting.

Irregular Plural Nouns Ending in F or FE

Some nouns ending in f or fe change to ves in the plural form. However, not every f or fe noun follows this rule.

Singular	Plural
leaf	leaves
knife	knives
wife	wives
life	lives
wolf	wolves
shelf	shelves
loaf	loaves
calf	calves
half	halves
thief	thieves
elf	elves
self	selves
scarf	scarves

Examples:

• One leaf fell from the tree.
• Many leaves fell from the tree.
• The knife is sharp.
• The knives are sharp.

Common exceptions:

Singular	Plural
chief	chiefs
roof	roofs
belief	beliefs
safe	safes
cliff	cliffs

Latin and Greek Irregular Plural Nouns

Some irregular plurals come from Latin or Greek. These words often appear in science, school, research, and formal English. However, beginners should learn the common irregular nouns first.

Singular	Plural
cactus	cacti
fungus	fungi
nucleus	nuclei
radius	radii
stimulus	stimuli
analysis	analyses
crisis	crises
thesis	theses
diagnosis	diagnoses
phenomenon	phenomena
criterion	criteria
bacterium	bacteria
curriculum	curricula
appendix	appendices
matrix	matrices

Examples:

• The analysis is complete.
• The analyses are complete.
• This phenomenon is strange.
• These phenomena are strange.

Compound Irregular Plural Nouns

Some compound nouns become plural by changing the main noun, not always the last word. For example, mother-in-law becomes mothers-in-law.

Singular	Plural
mother-in-law	mothers-in-law
father-in-law	fathers-in-law
brother-in-law	brothers-in-law
sister-in-law	sisters-in-law
son-in-law	sons-in-law
daughter-in-law	daughters-in-law
passer-by	passers-by
runner-up	runners-up
attorney general	attorneys general
court-martial	courts-martial

Examples:

• My sister-in-law is kind.
• My sisters-in-law are kind.
• A passer-by helped us.
• Two passers-by helped us.

When to Use Irregular Plurals in English

Irregular plurals appear in everyday speech, school grammar, reading, writing, and exams. Therefore, learning them helps you use English more accurately.

You will often use irregular plurals when talking about:

• people: man → men, woman → women, child → children
• body parts: tooth → teeth, foot → feet
• animals: mouse → mice, goose → geese, sheep → sheep
• school subjects: analysis → analyses, criterion → criteria
• family relations: mother-in-law → mothers-in-law

Irregular Plural Nouns in Sentences

Sentence pairs help you understand irregular plurals in real use. Moreover, they show how verbs and pronouns change with singular and plural nouns.

Singular Sentence	Plural Sentence
The child is reading.	The children are reading.
One man is waiting.	Two men are waiting.
The woman is speaking.	The women are speaking.
My tooth hurts.	My teeth hurt.
His foot is cold.	His feet are cold.
A mouse is in the kitchen.	Two mice are in the kitchen.
The goose is near the lake.	The geese are near the lake.
One deer crossed the road.	Three deer crossed the road.
This knife is sharp.	These knives are sharp.
A leaf fell down.	Many leaves fell down.
The person is waiting outside.	The people are waiting outside.
This series is popular.	These series are popular.

Common Mistakes with Irregular Plural Nouns

Many learners add -s to irregular nouns, but this often creates incorrect forms. Instead, learn the correct plural form as a full word.

Incorrect	Correct
childs	children
mans	men
womans	women
persons	people
tooths	teeth
foots	feet
mouses	mice
gooses	geese
oxes	oxen
sheeps	sheep
deers	deer
leafs	leaves
knifes	knives
wolfs	wolves
analysises	analyses

Tips:

• Use children, not childs.
• Use men, not mans.
• Use mice, not mouses.
• Use sheep, not sheeps.
• Use leaves, not leafs.

FAQs

Summary

Irregular plural nouns do not follow the normal plural rules. Instead, they may change spelling, change vowels, take special endings, or stay the same.

In this article, you learned 100 irregular plural nouns in English with examples and sentences, including common irregular nouns, vowel-change nouns, same-form plurals, f/fe → ves plurals, Latin and Greek forms, compound nouns, sentence pairs, and common mistakes. As a result, you can now use irregular plural nouns more confidently in writing, speaking, and schoolwork.

Read More

• List of Nouns in English
• Possessive Nouns in English
• Proper Nouns for People in English
• Singular and Plural Nouns Examples