Latin Plurals in English | Usage Tips

Last week, I wrote about awkward plurals used in English, focusing mostly on the linguistic history related to why we say the things we do. Today’s post is a bit different. While there is a bit about etymology, there are several other practical tips and bits that can be used daily with words derived from Latin.

Definitions

The nuts and bolts of getting on with today’s topic relies on knowing a bit about Latin declensions. But since most people weren’t subjected to the horrors I faced in secondary, I’ll go lenient. First off, declensions are simply classifications of words that have certain inflections. In Latin, there are five telling us whether to add -i, -ae, -a, etc. to create a plural form (Green 2015, 30–1). The real kicker, however, is that the application of these inflections seems to be randomly applied in English and for good reason: they are. (Fowler and Burchfield 2000, 442)

Come with Us

Making plurals from words ending with -us can be controversial for several reasons. The main one comes from differing opinions of what is “proper.” For example, Latin second-declension words ending in -us can generally be inflected with -i to make a plural form—Alumnus becomes alumni; cactus, cacti; fungus, fungi; and locus, loci (Fowler and Burchfield 815). While words in this classification can have the -i plural inflection in English, many, but not all, can also take on the -es ending, so we can have secondary English plurals like funguses and cactuses. However, locus cannot be locuses nor can alumnus be alumnuses. Sometimes with words like cactus, the plural form depends on context. In general use, cactuses is preferred, but in a botanical/scientific context, cacti is preferred (Fowler and Burchfield 815; Garner 2003, 122). There are no standard rules with this class of nouns, so it is important to check with your preferred dictionary and style guide to ensure you get it right.

With Latin fourth-declension words, the plural form of -us words in English is rarely anything but -es, and certainly never -i. So, we end up with words like prospectuses, apparatuses, sinuses, and others. (Fowler and Burchfield 815). You are probably asking yourself how you could possibly know what these Latin declensions are. There are two ways to approach it. The long way is to take Latin or look in a Latin dictionary. The short way is to ignore the rules and rely on English dictionaries and spell check.

Third-declension Latin loanwords ending in -us include corpus, genus, and opus. And these are made plural with -a, giving us corpora, genera, and opera, respectively. With these, -es is almost never used. I think I can see you eyeing opera and wondering what is going on there since we have operas. Good catch. This one is a bit awkward. Like with several other words adopted into English, we decided to make up our own rules. Yes, the plural of opus, meaning “work,” usually in relation to an artistic work, is opera, and an alternative plural is opuses, which falls into the “almost never” category just mentioned. At the same time, we have opera as a singular noun meaning “a drama set to music,” and it is made plural by adding -s. If anything, one can walk away knowing that opus, opera, opuses, and operas demonstrate that English is convoluted, and often unnecessarily so.

The big problem with -us words, as if there weren’t enough problems already, comes from words with Greek roots being treated as those with Latin roots. An often-cited example is octopus. For the record, the inflected -es plural is generally the preferred form. Fowler and Burchfield (539) are pretty clear, “The only acceptable pl. in English is octopuses.” Garner (566) supports this opinion explicitly as does Sabin (2001, 204). The problem with using the plural octopi is that the -i inflection is a Latin form, and it is being applied to a word of Greek origin. While a case can be made that Late Latin took on several Greek derivatives and then employed Latin rules, it still seems a bit forced. And even if some dictionaries list octopi as an acceptable alternative, don’t do it. Sometimes for comedic effect, some may use the classical Greek -des inflection as in octopodes, but as that has never been accepted as a proper form; stick with -es.

It is a good idea to exercise the same general approach with other Greek derivatives that were brought into Latin, like hippopotamus and rhinoceros. Yes, I know that rhinoceros ends with -os, but there is still a propensity toward making the plural rhinoceri for some reason, so I’m throwing it into the same bucket. Just write rhinoceroses.

Conclusion

I’m skipping out on -um nouns today. In a previous article, I went over the difference between datum and data. The same rules generally apply to other -um nouns, so yes, you can have an agenda and several agendas. I may do another article specifically on those and a few others. It has been fun reading and writing about etymology over the past couple of weeks. I hope the information has been interesting enough for you.

References

Agelo, John. 2010. The Origins and Development of the English Language. 6th ed. Boston: Wadsworth.

Fowler, H. W. and R. W. Burchfield. 2000. New Fowler’s Modern English Usage. 3rd ed. New York: Oxford University Press.

Garner, Bryan A. 2003. Garner’s Modern American Usage. New York: Oxford University Press.

Green, Tamara M. 2015. The Greek & Latin Roots of English. 5th ed. London: Rowman & Littlefield.

Sabin, William A. 2010. The Gregg Reference Manual: A Manual of Style, Grammar, Usage, and Formatting—Tribute Edition. 11th ed. New York: McGraw-Hill.