Plural Forms of Nouns

Regular Nouns

Most nouns simply add an "s" to become plural.

  • Dog-dogs, finger-fingers, car-cars

Words ending in a "ch" or "s" sound, usually add "es" to become plural.

  • Box-boxes, bus-buses, church-churches

Words ending in "f" or "fe" usually change the ending to "ves" to become plural.

  • Life-lives, leaf-leaves, wolf-wolves

This rule, however, has many exceptions. The plural of "safe" is "safes," because "saves" means something else.  Other exceptions exist for no obvious reason.

  • Roof-roofs, dwarf-dwarfs

Words that end in "o" are pluralized by adding either "s" or "es."  If there is a vowel before the "o", just add an "s."

  • Radio-radios, video-videos

If there is a consonant before the "s", there is no consistent rule.

  • Potato-potatoes, hero-heroes


  • Photo-photos, memo-memos

Words ending in "y" often form plurals by changing the "y" to "i" and adding "es."

  • Cry-cries, fly-flies, party-parties

People's names are an exception to most of these rules.  Chuck Berry and his family would be known as the Berrys.

Irregular Nouns

Some words don't change when they become plural.  This most often applies to animals.

  • Moose-moose, deer-deer, fish-fish

Some words ending in "us" form plurals by changing the "us" to "i."

  • Thesaurus-thesauri, syllabus-syllabi, focus-foci

Some words ending in "x" are pluralized with the ending "ices."

  • Index-indices, appendix-appendices

A few words ending in "is" form plurals by changing "is" to "es."

  • Crisis-crises, thesis-theses

There are many exceptions which seem to follow no pattern at all.  Here are some examples:

  • Foot-feet
  • tooth-teeth
  • child-children
  • person-people
  • man-men
  • woman-women


Don't use apostrophes to create plurals unless you have a good reason.  Use apostrophes if you are pluralizing letters.

  • He played for the Oakland A’s.
  • I got B's and C's on my report card.

Apostrophes can be used to pluralize abbreviations and acronyms, only if the abbreviation could cause confusion.  Acronyms like GA or BU or SS should be pluralized with an apostrophe s because GAs and BUs look like words, and SSs just looks confusing.  However, DVDs, CDs, and PhDs are not likely to be a source of confusion.  They do not need apostrophes.

Unusual Singular Forms

A few words are almost always seen in their plural form, so much so that many people do not realize that these words are plural.

Plural Form    Singular Form
dice               die
data              datum (a single piece of information)
media           medium
criteria           criterion