Grammatically Correct: The writer's essential guide to punctuation ...

SOME WORDS OF ITALIAN ORIGIN THAT END IN 0
CHANGE TO!, BUT MAY ALTERNATIVELY ADDS
concerto
basso
concerti or concertos
bassi or bassos
LATIN WORDS ENDING IN US CHANGE TO I
For some-not all-it is acceptable to add es instead.
alumnus alumni
stimulus stimuli
locus loci
focus foci or focuses
fungus fungi or funguses
nucleus nuclei or nucleuses
radius radii or radiuses
PROBLEM WORDS
In cases where both forms are legitimate, the Latin plural is
preferred in more formal writing.
LATIN WORDS ENDING IN UM CHANGE TO A
For some-not all-it is acceptable to add s instead.
bacterium
medium
datum
millennium
memorandum
symposium
honorarium
bacteria
media
data
millennia or millenniums
memoranda or memorandums
symposia or symposiums
honoraria or honorariums
In cases where both forms are legitimate, the Latin plural is
preferred in more formal writing.
Note that for some Latin words the English plural has become
the standard. For example, pluralizing museum and auditorium
as musea and auditoria would look more pretentious than correct.
LATIN WORDS ENDING IN A ADD AN E
For some-not all-it is acceptable to add s instead.
alumna
larva
alumnae
larvae
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