Irregular Plurals in English

Vocabulary practice flashcards covering irregular plurals in English, including -ves endings, Latin/Greek plurals, invariant nouns, singular nouns ending in -s, normally plural nouns, and distinctions among people, persons, and peoples.

Zero-plural nouns (invariant)

Nouns whose singular and plural forms are identical, such as sheep, deer, fish, aircraft, species, series, and means.

Plurals in -ves exceptions

Nouns ending in -f or -fe that do not take -ves in the plural, including roof (roofs), belief (beliefs), chief (chiefs), and safe (safes).

Oxen

The irregular plural form of ox.

Lice

The irregular plural form of louse.

Calves

The plural form of calf, formed by changing -f to -ves.

Loaves

The plural form of loaf, formed by changing -f to -ves.

Analyses

The plural form of analysis (Greek/Latin origin ending in -is changing to -es).

Crises

The plural form of crisis (Greek/Latin origin ending in -is changing to -es).

Hypotheses

The plural form of hypothesis (Greek/Latin origin ending in -is changing to -es).

Phenomena

The plural form of phenomenon (Greek origin ending in -on changing to -a).

Criteria

The plural form of criterion (Greek origin ending in -on changing to -a).

Data

The plural form of datum (/ˈdeɪtəm/ or /ˈdætəm/).

Bacteria

The plural form of bacterium.

Curricula

The Latin plural form of curriculum.

Stimuli

The Latin plural form of stimulus.

Alumni vs. Alumnae

Alumni (/əˈlʌmnaɪ/) is the plural of alumnus (male graduate), while alumnae (/əˈlʌmniː/) is the plural of alumna (female graduate).

Memoranda / Memorandums

The two accepted plural forms of memorandum.

Nouns that look plural but are singular

Words ending in -s that grammatically take singular verbs, including news, mathematics, politics, economics, linguistics, physics, and measles.

Politics (grammatical agreement)

Treated as singular when referring to the general subject or activity, but can take a plural verb when referring to the specific politics of a particular issue.

Normally plural nouns

Nouns used predominantly in the plural form with plural verbs, such as people, police, cattle, clothes, scissors, trousers, jeans, glasses, spectacles, thanks, congratulations, surroundings, earnings, belongings, and outskirts.

People (vs. Persons vs. Peoples)

Used to denote individuals in general as the common plural of person.

Persons

The plural of person reserved primarily for formal or legal contexts.

Peoples

The plural of people used to denote distinct ethnic, cultural, or national groups (e.g., Indigenous peoples).