FORMATION OF PLURALS IN WORDS OF FOREIGN ORIGIN

Plurals of nouns taken into English from other languages sometimes follow the laws of inflexion of those languages. But often, in non-technical works, additional forms are used, constructed after the English manner. Print as below, in cases where the author does not object. In scientific works the scientific method must of course prevail:

SING.addendumPL.addenda[26]
alkalialkalis
alumnusalumni
amanuensisamanuenses
analysisanalyses
animalculumanimalcula
antithesisantitheses
apexapices
appendixappendices
arcanumarcana
automatonautomata
axisaxes
banditbanditti
basisbases
beaubeaux
bronchusbronchi
calculuscalculi
calixcalices
chrysalischrysalises
coagulumcoagula
corrigendumcorrigenda[{26}]
cortexcortices
crisiscrises
criterioncriteria
datumdata
desideratumdesiderata
dilettantedilettanti
effluviumeffluvia
elenchuselenchi
ellipsisellipses
ephemeraephemerae
epithalamiumepithalamia
equinoxequinoxes
erratumerrata
focusfocuses (fam.)
formulaformulae
fungusfungi
geniusgeniuses[27]
(meaning a person or persons of genius)
genusgenera
helixhelices
hypothesishypotheses
ignis fatuusignes fatui
indexindexes[28]
irisirises
laminalaminae
larvalarvae
lemmalemmas[29]
librettolibretti
matrixmatrices
maximummaxima
mediummediums (fam.)
memorandummemorandums[30]
(meaning a written note or notes)
metamorphosismetamorphoses
miasmamiasmata
minimumminima
nebulanebulae
nucleusnuclei
oasisoases
papillapapillae
parenthesisparentheses
parhelionparhelia
phenomenonphenomena
radiusradii
radixradices
sanatoriumsanatoria
scholiumscholia
spectrumspectra
speculumspecula
stamenstamens
stimulusstimuli
stratumstrata
synopsissynopses
terminustermini
thesistheses
virtuosovirtuosi
volsellavolsellae
vortexvortexes (fam.)

FOOTNOTES:

[26] See reference to these words for another purpose on [p. 33].—H. H.

[27] Genius, in the sense of a tutelary spirit, must of course have the plural genii.—H. H.

[28] In scholarly works, indices is often preferred, and in the mathematical sense must always be used.—H. H.

[29] But lemmata in botany or embryology.—H. H.

[30] But in a collective or special sense we must print memoranda.—H. H.