Most English nouns form their plural by adding either -s (books, bands, bells) or -es (boxes, bunches, batches). These plural forms are said to follow a regular pattern.
However, English, being the wonderfully complex language it is, doesn't always adhere strictly to rules. A subset of nouns deviate from this pattern, forming their plurals in unconventional ways.
For instance, some nouns undergo a vowel change, like "man" becoming "men" or "foot" changing to "feet."
Others add an "-en" suffix, such as "child" becoming "children" or "ox" transforming into "oxen."
Additionally, there are irregular nouns that maintain their singular form in plural, like "deer" and "sheep."
Understanding these irregular plural forms adds depth to English language learning, showcasing its richness and diversity.
Irregular Plural Nouns
"The Penguin Writer's Manual"
"There are no easy rules, unfortunately, for irregular plurals in English. They simply have to be learnt and remembered."
Not all nouns conform to the standard pattern. In fact, some of the most common English nouns have irregular plural forms, such as woman/women and child/children. In addition, several nouns have alternative plurals, one regular and the other irregular.
In regard to these alternative forms, there are no strict rules to guide our use of them.
"The Cambridge Encyclopedia of the English Language"
"People have to learn which form to use as they meet the words for the first time, and must become aware of variations in usage. When there is a choice, the classical [irregular] plural is usually the more technical, learned, or formal, as in the case of formulas vs. formulae or curriculums vs. curricula. Sometimes, alternative plurals have even developed different senses, as in the cases of (spirit) mediums vs. (mass) media, or appendixes (in bodies or books) vs. appendices (only in books)."
As you'll see in the list that follows, many words with irregular plurals are loanwords that have kept their foreign plural forms (or at least held on to those forms as alternatives to regular English plurals).
100 Irregular Plural Nouns List
In the list below, you'll find singular noun forms in the left column and the corresponding plural forms in the right column. When a noun has more than one plural form, the irregular one appears first, though that doesn't necessarily mean that the irregular form is more widely accepted than the regular form.
addendum | addenda or addendums |
aircraft | aircraft |
alumna | alumnae |
alumnus | alumni |
analysis | analyses |
antenna | antennae or antennas |
antithesis | antitheses |
apex | apices or apexes |
appendix | appendices or appendixes |
axis | axes |
bacillus | bacilli |
bacterium | bacteria |
basis | bases |
beau | beaux or beaus |
bison | bison |
bureau | bureaux or bureaus |
cactus | cacti or cactus or cactuses |
château | châteaux or châteaus |
child | children |
codex | codices |
concerto | concerti or concertos |
corpus | corpora |
crisis | crises |
criterion | criteria or criterions |
curriculum | curricula or curriculums |
datum | data |
deer | deer or deers |
diagnosis | diagnoses |
die | dice or dies |
dwarf | dwarves or dwarfs |
ellipsis | ellipses |
erratum | errata |
faux pas | faux pas |
fez | fezzes or fezes |
fish | fish or fishes |
focus | foci or focuses |
foot | feet or foot |
formula | formulae or formulas |
fungus | fungi or funguses |
genus | genera or genuses |
goose | geese |
graffito | graffiti |
grouse | grouse or grouses |
half | halves |
hoof | hooves or hoofs |
hypothesis | hypotheses |
index | indices or indexes |
larva | larvae or larvas |
libretto | libretti or librettos |
loaf | loaves |
locus | loci |
louse | lice |
man | men |
matrix | matrices or matrixes |
medium | media or mediums |
memorandum | memoranda or memorandums |
minutia | minutiae |
moose | moose |
mouse | mice |
nebula | nebulae or nebulas |
nucleus | nuclei or nucleuses |
oasis | oases |
offspring | offspring or offsprings |
opus | opera or opuses |
ovum | ova |
ox | oxen or ox |
parenthesis | parentheses |
phenomenon | phenomena or phenomenons |
phylum | phyla |
quiz | quizzes |
radius | radii or radiuses |
referendum | referenda or referendums |
salmon | salmon or salmons |
scarf | scarves or scarfs |
self | selves |
series | series |
sheep | sheep |
shrimp | shrimp or shrimps |
species | species |
stimulus | stimuli |
stratum | strata |
swine | swine |
syllabus | syllabi or syllabuses |
symposium | symposia or symposiums |
synopsis | synopses |
tableau | tableaux or tableaus |
thesis | theses |
thief | thieves |
tooth | teeth |
trout | trout or trouts |
tuna | tuna or tunas |
vertebra | vertebrae or vertebras |
vertex | vertices or vertexes |
vita | vitae |
vortex | vortices or vortexes |
wharf | wharves or wharfs |
wife | wives |
wolf | wolves |
woman | women |
Sources
- Crystal, David. "The Cambridge Encyclopedia of the English Language." 3rd Edition, Cambridge University Press, January 24, 2019.
- Manser, Martin. "Penguin Writers Manual." Penguin Reference Books, Stephen Curtis, Paperback, International Edition, UK ed. edition, Penguin UK, August 24, 2004.