100 Irregular Plural Nouns in English

The plural form of wolf is wolves. Guy Edwardes/Getty Images

by Richard Nordquist

There are no easy rules, unfortunately, for irregular plurals in English. They simply have to be learnt and remembered.
(S. Curtis and M. Manser, The Penguin Writer's Manual, 2002)

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.
 
But not all nouns conform to this standard pattern. In fact, some of the most common English nouns have irregular plural forms--such as woman/women and child/children.

(The reasons for this are briefly discussed in the article Plural Forms of English Nouns.) 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:

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).
(David Crystal, The Cambridge Encyclopedia of the English Language, 2nd ed. Cambridge University Press, 2003)

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).

List of 100 Irregular Plural Nouns in English

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.
SOURCES: The plural forms in this list are recognized by Merriam-Webster's Collegiate Dictionary (2003) and The American Heritage Dictionary of the English Language (2011).

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
prognosis	prognoses
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

Source: https://www.thoughtco.com/irregular-plural-nouns-in-english-1692634

Capital and Capitol

Commonly Confused Words

In the U.S. Capitol (pictured here), you'll hear talk about capital gains, capital punishment, capital cities, and capital letters. (Stefan Zaklin/Getty Images)      

by Richard Nordquist

Updated August 17, 2016 

The words capital and capitol are near-homophones: they sound almost the same but have different meanings.

Definitions

The noun capital has multiple definitions: (1) a city that serves as the seat of government; (2) wealth in the form of money or property; (3) an asset or advantage; (4) a capital letter (the type of upper-case letter used at the beginning of a sentence).

As an adjective, capital refers to punishment by death (as in "a capital offense") or a letter of the alphabet (in the form A, B, C rather than a, b, c).

The adjective capital can also mean excellent or highly important.

The noun capitol refers to the building in which a legislative assembly meets. (Remember that the o in capitol is like the o in the dome of a capitol building.)
 

Examples

• The dome of the United States Capitol is one of the most famous man-made landmarks in America.
• The capital of Alaska is Juneau. 
• "Hartford [Connecticut] had always struck him as a pleasantly hick city, a small forest of green-glass skyscrapers on the winding road to New York; when you descended out of the spaghetti of overpasses, there was a touching emptiness, of deserted after-hours streets and of a state capital's grandiose vacancies."
  (John Updike, "Grandparenting." The Maples Stories. Knopf, 2009)  
• "He began to dust off the top and there found all sorts of things—a forgotten pin box, a pill box with tacks in it, two knitting needles, and an out-of-date diary on which was written in capitals: THE AIDEN CYCLE."
  (Christina Stead, The Man Who Loved Children, 1940)
• "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts."
  (Arthur Conan Doyle, "A Scandal in Bohemia," 1891) 
• "Though many think capital punishment is not an effective deterrent to crime, others insist this is because criminals in the United States know they are not likely to be convicted of a capital crime and that if they are convicted, they are even less likely to be executed."
  (John S. Feinberg and Paul D. Feinberg, Ethics for a Brave New World, 2nd ed. Crossway, 2010)

Practice

(a) The United States _____ building is located in Washington, D.C., the _____ city of the U.S.
(b) "We lived with our grandmother and uncle in the rear of the Store (it was always spoken of with a _____ S), which she had owned some twenty-five years."
(Maya Angelou, I Know Why the Caged Bird Sings. Random House, 1969)
(c) "[T]he cost of starting a boardinghouse in San Francisco could be prohibitive, and very few newcomers to the West had the _____ to open the kind of establishment that Pleasant financed on Washington Street."
(Lynn Maria Hudson, The Making of "Mammy Pleasant": A Black Entrepreneur in Nineteenth-Century San Francisco. University of Illinois Press, 2003)

Answers to Practice Exercises: Capital and Capitol
(a) The United States Capitol building is located in Washington, D.C., the capital city of the U.S.
(b) "We lived with our grandmother and uncle in the rear of the Store (it was always spoken of with a capital ​S), which she had owned some twenty-five years."
(Maya Angelou, I Know Why the Caged Bird Sings. Random House, 1969)
(c) "[T]he cost of starting a boardinghouse in San Francisco could be prohibitive, and very few newcomers to the West had the capital to open the kind of establishment that Pleasant financed on Washington Street."
(Lynn Maria Hudson, The Making of "Mammy Pleasant": A Black Entrepreneur in Nineteenth-Century San Francisco; University of Illinois Press, 2003)

Source: https://www.thoughtco.com/capital-and-capitol-1692717?utm_campaign=grammartip&utm_medium=email&utm_source=cn_nl&utm_content=9072411&utm_term=