Most English nouns form their plural simply by adding “-s” or “-es” (e.g., cats, boxes). However, some words follow different pluralisation rules, often due to their Latin, Greek, or Old English origins.
This guide provides a categorised list of weird plural words forms, their origins, and how to use them correctly.
Common Irregular Plurals
These are everyday words with non-standard pluralisation rules.
| Singular | Plural | Example Sentence |
|---|---|---|
| Child | Children | The children played in the park. |
| Foot | Feet | She wore new shoes on her feet. |
| Man | Men | The men discussed their travel plans. |
| Mouse | Mice | There are mice in the attic. |
| Person | People | Many people attended the event. |
| Tooth | Teeth | He brushed his teeth twice a day. |
| Woman | Women | The women gathered for the meeting. |
Note:Â Women is one of the few English words where the vowel sound changes between singular and plural, like Goose/Geese.
Side note, I really think a group of laughing women should be called a cackle, check out our guide to collective nouns for correct terms.
Latin & Greek Plural Forms
Some words retain their original Latin or Greek endings.
| Singular (Latin/Greek) | Plural | Example Sentence |
|---|---|---|
| Bacterium | Bacteria | Some bacteria are harmful. |
| Criterion | Criteria | The criteria for selection were strict. |
| Datum | Data | The data suggests a different conclusion. |
| Medium | Media | The media covered the event widely. |
| Phenomenon | Phenomena | Many natural phenomena remain unexplained. |
| Stratum | Strata | Fossils were found in lower strata. |
Note: Forums is an accepted plural of forum alongside fora, but data is often treated as singular in modern usage.
Words with the Same Singular & Plural
These words do not change in plural form
| Singular & Plural | Example Sentence |
|---|---|
| Deer | We saw a herd of deer in the forest. |
| Fish | She caught several fish today. |
| Moose | A moose crossed the road. |
| Sheep | The farmer owns many sheep. |
| Series | This series is very addictive. |
Archaic & Uncommon Plurals
These words have older or rarely used plural forms.
| Singular | Plural | Modern Alternative |
|---|---|---|
| Brother | Brethren | Brothers |
| Louse | Lice | (No alternative) |
| Cul-de-sac | Culs-de-sac | Cul-de-sacs |
| Appendix | Appendices | Appendixes (for books) |
| Cow | Kine | Cows |
| Index | Indices | Indexes (for books) |
| Octopus | Octopuses | (Octopodes, but rarely used) |
Note: Brethren is archaic and mainly used in religious or fraternal contexts.
Plurals of Foreign Loanwords
English has borrowed words from many languages, and some retain their original plural forms.
| Singular (Foreign Origin) | Plural | Language of Origin |
|---|---|---|
| Graffito | Graffiti | Italian |
| Papyrus | Papyri | Greek |
| Gateau | Gateaux | French |
| Paparazzo | Paparazzi | Italian |
| Cactus | Cacti | Latin |
| Crisis | Crises | Greek |
| Thesis | Theses | Greek |
| Alumnus | Alumni | Latin |
Note: Graffiti is now often used as an uncountable noun in English, which is the same for individual Spagetto and the plural Spagetti.
Unusual & User-Suggested Plurals
Some words have alternative or controversial plurals.
| Singular | Plural | Comment |
|---|---|---|
| Pants | Pants | (Always plural in English) |
| Scissors | Scissors | (Always plural) |
| Tweezers | Tweezers | (Always plural) |
| Ginseng | Ginsengs | (Rare, when referring to multiple roots) |
| Music | Musics | (Used in academia for multiple styles) |
Frequently Asked Questions (FAQ)
Why is “data” sometimes singular and sometimes plural?
Traditionally, data is plural (from datum). However, in modern English, especially in computing, “data” is treated as uncountable and singular (e.g., The data is processed automatically).
Why do some words have multiple plural forms?
Words like octopus and index have Latin, Greek, and English pluralisation rules. Octopuses is more common, but octopodes is technically correct in Greek.
What’s the difference between “fish” and “fishes”?
Fish is standard when referring to multiple fish of the same species. Fishes is used when referring to multiple species (e.g., the fishes of the Amazon River).
What are some weird plurals in English?
“Ox” becomes “oxen” in the plural. This “en” ending is an older form of pluralisation that you can still find in some English words today. “Die” turns into “dice” in the plural, which is a bit unusual too.
These is another branch of terms too, such as the plural of people passing by, where “passerby” becomes “passersby” as a plural.
What are some newer funny plurals?
Niblings was coined in 1951 as a term for nieces and nephews collectively.
Key Takeaways
- Archaic plurals like brethren and indices are still used in some contexts as interesting plurals.
- Foreign loanwords often keep their original plural forms (e.g., paparazzo → paparazzi).
- Some words stay the same in singular and plural (e.g., deer, sheep).
- Modern alternatives exist for some archaic plurals (e.g., indexes instead of indices).
- Words like “pants” and “scissors” are always plural in English.
Understanding irregular plurals is important for both native and non-native English speakers. Some words follow logical patterns, while others are exceptions due to historical influences.
English plurals are full of exceptions, borrowed words, and evolving rules. While some words follow simple pluralization rules, others retain their original foreign forms or take on new meanings in modern English.
Do you know more unusual plurals? If you know of rare or interesting ones we’ve missed, share them in the comments!
