Simple Notes

STUDY HOURs:
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

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