Non-Standard Plural Forms of Common Nouns
Another tricky aspect of the English language is forming the plural form of certain common nouns. The standard way to pluralize a word in English is to add an “s” at the end of the word. However, there are many exceptions to this.
Many of these non-standard or irregular plurals are non-intuitive, and the only way to know them is to memorize them, or failing that, look them up in a dictionary. Below is a list showing the non-standard plural form of some of the more common nouns.
| Singular form addendum alumna alumnus analysis antenna appendix bacterium basis bureau bus census crisis criterion ellipsis erratum focus formula forum gas hypothesis index matrix medium memorandum nucleus parenthesis phenomenon plateau surplus symposium | Plural form addenda alumnae alumni analyses attennae (feelers); or antennas (areials) appendixes or appendices bacteria bases bureaus buses censuses crises criteria ellipses errata focuses formulas or formulae forums (NOT fora) gases hypotheses indexes (book); or indices (math, statistics) matrices mediums or media (see dictionary for context) memorandums or memoranda nuclei parentheses phenomena plateaus surpluses symposiums or symposia |
The above are the best examples I could come up with when I researched and wrote this page. If you think of other non-standard plural forms, go ahead and add them to your own list. If you think of a good one that I missed, please e-mail it to me via the “Contact” link at the bottom of this page.