Irregular Plural Noun | Definition, Examples, List and Exercise

Irregular Plural Noun do not follow a Regular Pattern of Pluralization. We have explored pluralization rules for Regular plural Nouns that set them apart from Irregular Nouns.

What is an Irregular Plural Noun?

There’s a typical pattern to change singular into plural. The noun that don’t follow this pattern is known as Irregular plural noun. For Example, the plural of woman is “women” and the plural of “man” is “men.” Let’s explore what are irregular plurals and what pluralization rules they follow.

Irregular Plural Noun Definition: 

The Nouns that don’t follow the standard pattern of pluralization are called as Irregular Plural Nouns. They mar look like their singular form or carry in pronunciation and spelling with their plural forms.

Irregular Plural Nouns Examples:

Singular	Plural
Tooth	Teeth
Foot	Feet
Child	Children
Man	Men
Radius	Radii
Locus	Locci
Woman	Women

Irregular Plural Nouns Sentences:

• Two tiny mice are hiding under the table.
• Children are playing in the Garden.
• All the women of our street are attending cooking classes.
• My two teeth are aching.
• Cells have protons and neutrons contained in nuclei.

Formation of Irregular Plural Noun:

• Changing the Vowel
• Changing -f or -fe
• Changing -us to -i
• Changing -is to -es
• Changing -man to -men
• Irregular Forms
• Some Singular have Same Plural forms

Rules to form Irregular Plural Nouns:

Changing the Vowel:

Some Irregular Plural Forms have changes in the vowels during pluralization.

Examples:

Singular	Plurral
Men	Man
Tooth	Teeth
Foot	Feet

Changing -f or -fe:

Nouns ending in -f or -fe usually change the ending to -ves when forming the plural.

Changing “-us” to “-i”:

The pluralization rule for the Nouns ending in “-us” is to change “-us” to “-i” while forming plurals.

Examples:

Singular	Plural
Stimulus	Stimuli
Fungus	Fungi
Nucleus	Nuclei

Changing-is to -es:

The rule to pluralize words ending with “-is” is to change “-is” into “-es.”

Examples:

Singular	Plural
Hypothesis	Hypotheses
Synthesis	Syntheses
Emphasis	Emphases

Changing -man to -men:

Nouns ending in -man often change to -men in the plural form. This is a way to make the plural form more gender-neutral.

Examples:

Singular	Plural
Fireman	Firemen
Policeman	Policemen
Chairman	Chairmen

Irregular Forms:

Some irregular Plural Nouns don’t follow a specific pattern for pluralization. Here are examples.

Examples:

Singular	Plural
Curriculum	Curricula
Datum	Data
Child	Children

No Change in Form:

Some Nouns have the same Singular and Plural forms. They remain the same and there is no change in spellings or forms during pluralization.

Examples:

Singular	Plural
Sheep	Sheep
Fish	Fish
Swine	Swine

list of irregular plural nouns

Here is the Irregular Plural Nouns List.

• Addendum – Addenda
• Aircraft – Aircraft
• Alumnus – Alumni
• Analysis – Analyses
• Appendix – Appendices
• Axis – Axes
• Bacterium – Bacteria
• Barracks – Barracks
• Basis – Bases
• Buffalo – Buffaloes / Buffalos
• Cactus – Cacti
• Calf – Calves
• Census – Censuses
• Cherub – Cherubim
• Child – Children
• Corps – Corps
• Crisis – Crises
• Criterion – Criteria
• Curriculum – Curricula
• Datum – Data
• Deer – Deer
• Diagnosis – Diagnoses
• Die – Dice
• Echo – Echoes
• Elf – Elves
• Erratum – Errata
• Fish – Fish
• Focus – Foci
• Foot – Feet
• Formula – Formulae
• Fungus – Fungi
• Genus – Genera
• Goose – Geese
• Half – Halves
• Index – Indices
• Knife – Knives
• Leaf – Leaves
• Life – Lives
• Loaf – Loaves
• Louse – Lice
• Louse – Lice
• Man – Men
• Matrix – Matrices
• Medium – Media
• Memorandum – Memoranda
• Millennium – Millennia
• Mouse – Mice
• Nucleus – Nuclei
• Octopus – Octopuses / Octopi
• Ox – Oxen
• Person – People
• Phenomenon – Phenomena
• Potato – Potatoes
• Radius – Radii
• Rhino – Rhinos
• Salmon – Salmon
• Series – Series
• Sheep – Sheep
• Shelf – Shelves
• Spectrum – Spectra
• Stadium – Stadia
• Stimulus – Stimuli
• Swine – Swine
• Syllabus – Syllabi
• Thief – Thieves
• Tomato – Tomatoes
• Tooth – Teeth
• Trout – Trout
• Vertex – Vertices
• Wife – Wives
• Wolf – Wolves
• Woman – Women

Irregular Plural Nouns List pdf:

Download Irregular Pronouns list pdf below:

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Irregular Plural Nouns Exercises:

Change into Irregular Plural Nouns.

1. Man
2. Foot
3. Child
4. Analysis
5. Crisis
6. Ox
7. Thesis
8. Datum
9.  Woman
10.  Tooth
11.  Mouse
12.  Crisis
13.  Leaf
14.  Calf
15.  Thief
16.  Child
17.  Elf
18.  Potato
19.  Ox
20.  Goose
21.  Thesis
22. Medium
23. Alumnus

Here is the answer key.

1. Men
2. Feet
3. Children
4. Analyses
5. Crises
6. Oxen
7. Theses
8. Data
9. Women
10. Teeth
11. Mice
12. Crises
13. Leaves
14. Calves
15. Thieves
16. Children
17. Elves
18. Potatoes
19. Oxen
20. Geese
21. Theses
22. Media
23. Alumni