Words borrowed from classical Greek and Latin have tended to keep their foreign plurals in English longer than most other foreign borrowings.
- Plural Forms of English Nouns
- Confused Words: Criterion and Criteria
- Confused Words: Media, Medium, Mediums
- Count Noun
- Double Plural
- A List of 100 Irregular Plural Nouns in English
- What Do You Get When One Ignoramus Meets Another Ignoramus?
Examples and Observations:
- "Scientists divide the bacteria [singular, bacterium] into groups based on shape: spherical cells, which are labeled as cocci (sing., coccus); rod-shaped cells, called bacilli (bacillus); curved rods, known as vibrios; and spiral-shaped bacteria."
(Sherman Hollar, A Closer Look at Bacteria, Algae, and Protozoa. Britannica Educational Publishing, 2012)
- "This step-by-step guide to creating and analyzing linguistic corpora [singular, corpus] discusses the role that corpus linguistics plays in linguistic theory."
(Charles F. Meyer, English Corpus Linguistics: An Introduction. Cambridge University Press, 2002)
- "A matrix is just a rectangular array of rows and columns of numbers. Matrices, however, represent another kind of two-dimensional numerical object and, what is more, they pervade nearly all of higher mathematics, both pure and applied."
(Peter M. Higgins, Numbers: A Very Short Introduction. Oxford University Press, 2011)
- "Some of the types of studies needed are concept analyses [singular, analysis], content validation, construct and criterion-related validation, consensus validation, studies of accuracy of nurses' diagnoses [singular diagnosis], and implementation studies."
(Margaret Lunney, "Nursing Diagnosis and Research." Nursing Diagnoses 2009-2011: Definitions and Classification. Wiley-Blackwell, 2009)
- Divided Usage
"English has borrowed words from nearly every language with which it has come into contact, and particularly for nouns from Latin, Greek, Hebrew, and French, it has often borrowed their foreign plurals as well. But when loan words cease to seem 'foreign,' and if their frequency of use in English increases, they very often drop the foreign plural in favor of a regular English -s. Thus at any given time we can find some loan words in divided usage, with both the foreign plural (e.g., indices) and the regular English plural (e.g., indexes) in Standard use. And occasionally we’ll find a semantic distinction between the two acceptable forms, as with the awe-inspiring Hebrew cherubim and the chubby English cherubs."
(Kenneth G. Wilson, The Columbia Guide to Standard American English. Columbia University Press, 1993)
"The plural of stigma is either stigmas or stigmata . . .. Stigmas is the anglicized plural--to anglicize means to make English, conform to English modes of spelling, pronunciation, and usage. Stigmata, the Latinate plural, . . . refers to marks resembling the wounds on the crucified body of Jesus Christ . . .."
(Charles Harrington Elster, Verbal Advantage: Ten Easy Steps to a Powerful Vocabulary. Random House, 2009)
"In Classical Latin, the word agenda was the plural form of agendum, which referred to an item of business placed before the Roman Senate. Borrowed into English, the singular form of this word became agend, now obsolete. In Modern English, agenda has taken the place of agend as a singular noun, and denotes the set or list of such items, as in The agenda for the meeting has not yet been set. If a plural of agenda is required, the form should be agendas . . ..
"The evolution of the word agenda as a singular noun thus anticipates similar developments that are now taking place with such words as data and media."
(The American Heritage Guide to Contemporary Usage and Style. Houghton Mifflin, 2005)
- The Latin and Greek -a Plural
"Because of its exceptional divergence in form from all other patterns of English plural formation, the Latin and Greek -a plural has shown a tendency to be reinterpreted as a non-count form, or as a singular with its own -s plural. This tendency has progressed furthest in agenda and has met with varying degrees of acceptance in candelabra, criteria, data, media, and phenomena."
(Sylvia Chalker and Edmund Weiner, Oxford Dictionary of English Grammar. Oxford University Press, 1994)
- Subject-Verb Agreement With Foreign Plurals
"Well-recognized foreign plurals require plural verbs if they do not represent a singular unit.
Your criteria for grading my report are unfair.Criteria, the plural form of criterion, means 'standards of rules.' This word has origins in the Greek language. Phenomena, the plural of the Greek phenomenon, is another example of plural usage.
Her upper vertebrae were crushed in the accident.The singular of the Latin-derived vertebrae is vertebra."
(Lauren Kessler and Duncan McDonald, When Words Collide, 8th ed. Wadsworth, 2012)