Spelling Tip: Latin and Greek Plurals

This spelling tip examines the various endings of plural words derived from Latin and Greek.

Nouns that originated from Latin and Greek are common in scientific and medical writing.

The preferred plural form of many of these words is the same as in the original language. But for other plurals, the usual English rules of adding "s" or "es" now apply. Some words are in transition, either form being commonly used.

Examples

Table 1 shows common traditional endings for Latin or Greek singular nouns and their corresponding plural endings.

Table 1.
Common Latin and Greek Noun Endings

Singular ending		Plural ending
-a	→	-ae
-en	→	-ina
-ex	→	-ices
-is	→	-es
-itis	→	-itides
-ix	→	-ices
-on	→	-a
-um	→	-a
-us	→	-i

Table 2 presents singular and plural forms of selected nouns derived from Latin and Greek. English forms are shown in bold.

Some dictionaries indicate that the two plural forms—traditional and English—occur with equal frequency. However, the acceptability of an English plural form may differ by publication.

Caution: Read the dictionary entry carefully. Sometimes the English plural is used for only a narrow definition of the term.

Table 2.
Singular and Plural Nouns Derived From Latin and Greek

Singular form	Plural form
alga	algae or algas
analysis	analyses
bacterium	bacteria
basis	bases
criterion	criteria or criterions
datum	data
focus	foci or focuses
foramen	foramina or foramens
formula	formulae or formulas
fungus	fungi or funguses
genus	generaa
hypothesis	hypotheses
index	indices (math) or indexes
larva	larvae or larvas
matrix	matrices or matrixes
medium	media
nephritis	nephritides
nucleus	nuclei or nucleuses
parenthesis	parentheses
phenomenon	phenomena
radius	radii or radiuses
stimulus	stimuli
stratum	strata
synthesis	syntheses
vertebra	vertebrae or vertebras

^aThe plural ending for this word is an exception to the rule (see Table 1).

Quick Tips: Latin and Greek Plurals

1. Learn the traditional Latin and Greek plural endings (Table 1).




2. Check your dictionary (standard, medical) for the preferred plural form.



3. Above all, use the plural form consistently within your document.

Sources

Council of Science Editors, Style Manual Committee. Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers. 7th ed. Reston, VA: The Council; 2006

Merriam-Webster's Collegiate Dictionary. 11th ed. Springfield, MA: Merriam-Webster, Inc.; 2007.

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