Global Utilities

Academic Language and Learning

Irregular plural nouns used in scientific writing

Many nouns which are frequently used in scientific writing have come to us straight from Latin. A large number of these words have retained their Latin singular and plural forms. To a modern eye (or ear) these may look or sound strange. However it is necessary to get them right. Below are some of these words. To help you, the words have been grouped according to the rules that they follow. In some instances there are alternative forms of the plural, where this is the case it has been indicated.

Singular form Plural form
phenomenon
phenomena
criterion
criteria
medium media
addendum
addenda
forum fora / forums
stratum
strata / stratums
datum data
bacterium bacteria
quantum quanta
appendix
appendices / appendixes
index indices / indexes (two meanings)
vortex vortices / vortexes
matrix matrices / matrixes
antenna antennae (in the zoological sense)
formula
formulae / formulas
larva larvae
crisis crises
axis axes
basis
bases
hypothesis hypotheses
synopsis synopses
thesis theses
metamorphosis
metamorphoses
diagnosis
diagnoses
analysis
analyses
parenthesis parentheses
emphasis emphases
stimulus stimuli / stimuluses
radius
radii / radiuses
nucleus nuclei / nucleuses
genus genera
Content Approved by: Head of Language and Academic Skills
Page maintained by: Academic Language and Learning Lecturer
Last Updated: 15 November, 2010

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