English Grammar

Irregular Plural Noun | Definition, Examples, List and Exercise

Irregular Plural Nouns
Written by grammrary.com

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
ToothTeeth
FootFeet
ChildChildren
ManMen
RadiusRadii
LocusLocci
WomanWomen

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:

SingularPlurral
MenMan
ToothTeeth
FootFeet

Changing -f or -fe:

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

Examples:
SingularPlural
wolfWolves
WifeWives
leafLeaves

Changing “-us” to “-i”:

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

Examples:

SingularPlural
StimulusStimuli
FungusFungi
NucleusNuclei

Changing-is to -es:

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

Examples:

SingularPlural
HypothesisHypotheses
SynthesisSyntheses
EmphasisEmphases

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:

SingularPlural
FiremanFiremen
PolicemanPolicemen
ChairmanChairmen

Irregular Forms:

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

Examples:

SingularPlural
CurriculumCurricula
DatumData
ChildChildren

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
SheepSheep
FishFish
SwineSwine

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

List of Irregular Plural Noun

Irregular Plural Nouns List pdf:

Download Irregular Pronouns list pdf below:

Download pdf

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
Irregular Plural Nouns

Irregular Plural Nouns. Definition and Examples, formation and exercise.

About the author

grammrary.com

The author of Grammrary.com is a Certified TEFL Trainer from Arizona State University with over 7 years of experience teaching English to students from different cultures around the world. Teaching English is both his profession and passion, and he is dedicated to helping learners improve their language skills.

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