Irregular Noun Examples

An irregular noun is a noun that does not follow the typical rules for forming plurals. Instead of adding "s" or "es" to create the plural form, these nouns change in unique ways.

Here's a list of common irregular noun examples:

Irregular Nouns for Animals

  • Child → Children

  • Deer → Deer

  • Fish → Fish

  • Foot → Feet

  • Goose → Geese

  • Louse → Lice

  • Man → Men

  • Mouse → Mice

  • Ox → Oxen

  • Person → People

  • Tooth → Teeth

  • Woman → Women

Irregular Nouns for Objects

  • Aircraft → Aircraft

  • Appendix → Appendices

  • Axis → Axes

  • Cactus → Cacti

  • Crisis → Crises

  • Datum → Data

  • Die → Dice

  • Fungi → Fungus

  • Index → Indices

  • Knife → Knives

  • Leaf → Leaves

  • Life → Lives

  • Loaf → Loaves

  • Matrix → Matrices

  • Medium → Media

  • Mouse → Mice

  • Oasis → Oases

  • Parenthesis → Parentheses

  • Phenomenon → Phenomena

  • Radius → Radii

  • Stimulus → Stimuli

  • Thesis → Theses

  • Tooth → Teeth

  • Vertebra → Vertebrae

  • Wolf → Wolves

Irregular Nouns for People

  • Brother → Brethren

  • Child → Children

  • Foot → Feet

  • Gentleman → Gentlemen

  • Man → Men

  • Mouse → Mice

  • Ox → Oxen

  • Person → People

  • Police → Police

  • Tooth → Teeth

  • Woman → Women

Irregular Nouns for Miscellaneous Items

  • Analysis → Analyses

  • Antenna → Antennae

  • Bacterium → Bacteria

  • Crisis → Crises

  • Curriculum → Curricula

  • Datum → Data

  • Diagnosis → Diagnoses

  • Formula → Formulae

  • Hypothesis → Hypotheses

  • Oasis → Oases

  • Phenomenon → Phenomena

  • Radius → Radii

  • Series → Series

  • Species → Species

  • Thesis → Theses

  • Time → Times

  • Tooth → Teeth