Key Concepts
Many nouns that come from ancient languages, such as Latin or Greek, have retained their plural forms. However, some plurals of borrowed words are spelled according to the common English pattern of adding s or es. The following guidelines will be helpful in determining the spelling of the plural of a borrowed word.
- When the noun ends in is, change the is to es.
- axis—axes
- diagnosis—diagnoses
- emphasis—emphases
- parenthesis—parentheses
- When the noun ends in us, the us may be changed to i.
- stimulus—stimuli
However, sometimes es is added to form the plural.
- virus—viruses
- When the noun ends in um, the um is often changed to a.
- medium—media
However, some words that end in um follow the English pattern of forming the plurals.
- memorandum—memorandums
- When the noun ends in on, change the on to a.
- phenomenon—phenomena
- When the noun ends in a, add e.
- antenna—antennae
- A number of borrowed words that end in x follow the English pattern of forming plurals.
- appendix—appendixes
The plural form of some words may use either the foreign plural or the English plural spelling. Use a dictionary to determine the preferred spelling. The first spelling listed is considered the preferred form.
