Irregular Plural Nouns Exercises, Examples and List

Confusing Plural Forms Exercises

These exercises focus on Confusing Plural Forms

What Are Irregular Plural Nouns?

Irregular plural nouns are words that change form when they become plural. Unlike regular nouns, you cannot simply add -s or -es. Instead, the word changes in unique ways, or it may even stay the same.

For example:

Child → Children
Foot → Feet
Deer → Deer (no change)

List of 100 Most Common Irregular Plural Nouns in English

Here's an expanded table based on your provided data:

Word	Plural Form(s)	Example Sentence
Addendum	Addenda, Addendums	The document has two important addenda.
Aircraft	Aircraft	The hangar is full of military aircraft.
Alumna	Alumnae	The alumnae of the university gathered for an event.
Alumnus	Alumni	Many alumni attended the school’s anniversary.
Analysis	Analyses	His analyses of the data were very detailed.
Antenna	Antennae, Antennas	The car has two antennas for better reception.
Antithesis	Antitheses	The two ideas are direct antitheses of each other.
Apex	Apices, Apexes	They reached the apices of the mountain.
Appendix	Appendices, Appendixes	The book includes several appendices.
Axis	Axes	The Earth rotates on its axes.
Bacillus	Bacilli	Bacilli are rod-shaped bacteria.
Bacterium	Bacteria	Some bacteria are beneficial to humans.
Basis	Bases	The team worked from strong theoretical bases.
Beau	Beaux, Beaus	Her beaux all sent her flowers for her birthday.
Bison	Bison	A herd of bison grazed in the field.
Bureau	Bureaux, Bureaus	The government established new bureaux for efficiency.
Cactus	Cacti, Cactuses	Cacti thrive in arid environments.
Château	Châteaux, Châteaus	France is known for its historic châteaux.
Child	Children	The children are playing soccer in the yard.
Codex	Codices	Ancient codices were stored in the library.
Concerto	Concerti, Concertos	The orchestra performed several famous concertos.
Corpus	Corpora	The corpora of ancient texts were digitized.
Crisis	Crises	Several crises arose during the project’s timeline.
Criterion	Criteria, Criterions	The criteria for the award were very strict.
Curriculum	Curricula, Curriculums	The school updated its curricula to include coding.
Datum	Data	The data shows a significant increase in sales.
Deer	Deer, Deers	A group of deer was seen near the forest.
Diagnosis	Diagnoses	The doctor provided several diagnoses for the symptoms.
Die	Dice, Dies	He rolled the dice to start the game.
Dwarf	Dwarves, Dwarfs	The fantasy story featured a clan of dwarves.
Ellipsis	Ellipses	Use ellipses to show omitted text in a quotation.
Erratum	Errata	The book’s errata were listed on the last page.
Faux pas	Faux pas	Making a faux pas in formal settings can be embarrassing.
Fez	Fezzes, Fezes	The performers wore traditional fezzes during the show.
Fish	Fish, Fishes	We saw different kinds of fish at the aquarium.
Focus	Foci, Focuses	The study has two main foci.
Foot	Feet	His feet were tired after walking all day.
Formula	Formulae, Formulas	The scientist explained the formulae for the experiment.
Fungus	Fungi, Funguses	Fungi grow in damp and dark environments.
Genus	Genera, Genuses	These animals belong to different genera.
Goose	Geese	A flock of geese flew across the sky.
Graffito	Graffiti	The wall was covered with colorful graffiti.
Grouse	Grouse, Grouses	Hunters spotted several grouse in the woods.
Half	Halves	She cut the apple into two equal halves.
Hoof	Hooves, Hoofs	The horse’s hooves were shod with metal.
Hypothesis	Hypotheses	The scientist tested several hypotheses.
Index	Indices, Indexes	The book includes both subject and author indices.
Larva	Larvae, Larvas	Larvae eventually turn into butterflies.
Libretto	Libretti, Librettos	The libretti of the operas were beautifully written.
Loaf	Loaves	He bought two loaves of bread from the bakery.

Word	Plural Form(s)	Example Sentence
Locus	Loci	The loci of the earthquake were mapped accurately.
Louse	Lice	The child’s hair was checked for lice.
Man	Men	The men worked together on the project.
Matrix	Matrices, Matrixes	The mathematician solved the matrices easily.
Medium	Media, Mediums	Digital media have transformed how we communicate.
Memorandum	Memoranda, Memorandums	The manager distributed memoranda to the team.
Minutia	Minutiae	He paid attention to the minutiae of the design.
Moose	Moose	A herd of moose was grazing by the river.
Mouse	Mice	The mice nibbled on the crumbs under the table.
Nebula	Nebulae, Nebulas	Scientists observed nebulae through powerful telescopes.
Nucleus	Nuclei, Nucleuses	The nuclei of these cells are unusually large.
Oasis	Oases	The travelers rested at several oases along the route.
Offspring	Offspring, Offsprings	The animal’s offspring were healthy and strong.
Opus	Opera, Opuses	His greatest opera was performed last night.
Ovum	Ova	The ova were fertilized in the laboratory.
Ox	Oxen, Ox	The farmer used two oxen to pull the plow.
Parenthesis	Parentheses	The sentence includes additional information in parentheses.
Phenomenon	Phenomena, Phenomenons	Natural phenomena like auroras are fascinating.
Phylum	Phyla	This species belongs to one of the largest phyla.
Quiz	Quizzes	We had to take two quizzes this week.
Radius	Radii, Radiuses	The circle’s radii were measured accurately.
Referendum	Referenda, Referendums	Two referenda were held to decide the issue.
Salmon	Salmon, Salmons	He caught three large salmon in the river.
Scarf	Scarves, Scarfs	She bought several scarves as gifts.
Self	Selves	They learned to express their true selves.
Series	Series	The TV series was very popular among young people.
Sheep	Sheep	The shepherd watched over his sheep carefully.
Shrimp	Shrimp, Shrimps	We ordered a plate of shrimp for dinner.
Species	Species	This species of bird is endangered.
Stimulus	Stimuli	Bright lights can serve as stimuli for certain reactions.
Stratum	Strata	The geologist studied the rock strata carefully.
Swine	Swine	The farm was home to several swine.
Syllabus	Syllabi, Syllabuses	The professor handed out the course syllabi.
Symposium	Symposia, Symposiums	The academic symposia were well attended.
Synopsis	Synopses	The movie synopses gave a clear overview of each plot.
Tableau	Tableaux, Tableaus	The artist displayed his tableaux in the gallery.
Thesis	Theses	The graduate students presented their theses.
Thief	Thieves	The thieves escaped before the police arrived.
Tooth	Teeth	Her teeth are perfectly straight after braces.
Trout	Trout, Trouts	He caught two large trout during his fishing trip.
Tuna	Tuna, Tunas	The fisherman caught several tuna in the ocean.
Vertebra	Vertebrae, Vertebras	The X-ray revealed damage to two vertebrae.
Vertex	Vertices, Vertexes	The vertices of the triangle were labeled.
Vita	Vitae	The scholar’s vitae included numerous publications.
Vortex	Vortices, Vortexes	The plane encountered several dangerous vortices.
Wharf	Wharves, Wharfs	The ship docked at one of the wharves.
Wife	Wives	The wives attended a special gathering.
Wolf	Wolves	The wolves hunted in packs during the night.
Woman	Women	The women in the community worked together to organize the event.

Rules for Irregular Plural Nouns

Here are some common patterns for irregular plural nouns:

Singular Noun	Plural Noun	Rule
Child	Children	Change the word completely
Man	Men	Change the vowel sound (a → e)
Tooth	Teeth	Change the vowel (oo → ee)
Sheep	Sheep	No change
Cactus	Cacti	Change the ending (-us → -i)
Person	People	Entirely different plural form

Common Errors with Irregular Plural Nouns

Adding -s to irregular nouns
Example: Saying childs instead of children.
Using the wrong plural form
Example: Saying mans instead of men.
Forgetting no change nouns
Example: Saying sheeps instead of sheep.

FAQ About Irregular Plural Nouns

What are irregular plural nouns?

They are nouns that do not follow the regular rule of adding -s or -es to form plurals.

How can I remember irregular plural nouns?

Practice often, use flashcards, and learn the common patterns.

Are there any easy rules for irregular plural nouns?

No single rule fits all, but some patterns (e.g., man → men) can help.

Why do some nouns stay the same in plural form?

These words, like sheep or deer, come from Old English and never change.

Are irregular plural nouns common?

Yes, they are common in everyday English, so learning them is important.