Editing Plural form of words ending in -us

{{Short description|English language pluralization rules}}
{{DISPLAYTITLE:Plural form of words ending in -''us''}}
In [[English language|English]], the '''plural form of words ending in ''-us''''', especially those derived from [[Latin]],  often replaces ''-us'' with ''-i''. There are many exceptions, some because the word does not derive from Latin, and others due to custom (''e.g.'', ''[[campus]]'', plural ''campuses''). Conversely, some non-Latin words ending in ''-us'' and Latin words that did not have their  Latin plurals with ''-i'' form their English plurals with ''-i'', ''e.g.'', ''octopi'' is sometimes used as a plural for [[#Octopus|octopus]] (the standard English plural is octopuses). Most [[Linguistic prescription|Prescriptivists]] consider these forms incorrect, but [[Linguistic description|descriptivists]] may simply describe them as a natural evolution of language; some prescriptivists do consider some such forms correct (e.g. ''octopi'' as the plural of ''octopus'' being analogous to ''polypi'' as the plural of ''polypus'').

Some English words of Latin origin do not commonly take the Latin plural, but rather the regular English plurals in -(e)s: ''campus'', ''bonus'', and ''anus''; while others regularly use the Latin forms: ''radius'' (''radii'') and ''alumnus'' (''alumni''). Still others may use either: ''corpus'' (''corpora'' or ''corpuses''), ''formula'' (''formulae'' in technical contexts, ''formulas'' otherwise), ''index'' (''indices'' mostly in technical contexts, ''indexes'' otherwise).

==History==

In Latin, most [[Latin declension#d2|second declension]] [[grammatical gender|masculine]] nouns ending in ''-us'' form their plural in ''-i''. However, some Latin nouns ending in ''-us'' are not second declension (''cf.'' [[Latin grammar]]). For example, third declension [[neuter (grammar)|neuter]] nouns such as ''opus'' and ''corpus'' have plurals ''opera'' and ''corpora'', and fourth declension masculine and feminine nouns such as ''sinus'' and ''tribus'' have plurals ''{{lang|la|sinūs}}'' and ''{{lang|la|tribūs}}''.

Some English words derive from Latin idiosyncratically. For example, ''bus'' is a shortened form of ''[[bus#Name|omnibus]]'' 'for everyone', the [[ablative]] (and [[dative]]) plural of ''omnis'', and ''ignoramus'' is a verb form, 'we do not know'. ''Syllabus'' is a [[Late Latin]] (16th c.) word, derived from a misreading of the Greek ''sittybos'' "table of contents"; since it is not a classical word, some argue that it does not have a classical plural.<ref>{{cite web |title=Syllabus |url=https://www.etymonline.com/word/syllabus#etymonline_v_22509 |website=Online Etymological Dictionary |accessdate=21 October 2018}}</ref> However, the form ''syllabi'' is used and considered acceptable by some sources.<ref>{{cite web |title=Which Is The Correct Plural Spelling? (It's a Trick Question) |url=https://www.merriam-webster.com/grammar/tricky-plural-words-explained#:~:text=Syllabuses%20%26%20Syllabi&text=Both%20forms%20of%20the%20plural,you%20if%20you%20use%20syllabi. |website=Merriam-Webster |access-date=26 August 2023}}</ref>

==''Virus''==
The English plural of ''virus'' is ''viruses''.<ref>''A Dictionary of Modern English Usage'' (1950) H. W. Fowler, Oxford University Press</ref> In most speaking communities, this is non-controversial and speakers would not attempt to use the non-standard plural in -''i''. However, in computer enthusiast circles in the late 20th century and early 21st, the non-standard ''viri'' form (sometimes even ''virii'') was well attested, generally in the context of [[computer virus]]es.<ref>''VLAD Magazine'', Issues #1, #3, #5, #7</ref>  ''Viri'' is also found in some nineteenth-century sources.<ref>{{cite book |page=48 |url=https://archive.org/stream/homopathictreati00test#page/48 |title=A Homœopathic Treatise on the Diseases of Children |first=Alph[onse] |last=Teste |authorlink=Alphonse Teste |translator-first1=Emma |translator-last1=Côté |year=1854 |publisher=Moore, Anderson, Wilstach & Keys |location=Cincinnati}}</ref><ref>{{cite book |page=293 |url=https://archive.org/stream/in.ernet.dli.2015.506658/2015.506658.Diseases-Of#page/n327 |title=A Practical Treatise of Diseases of the Urinary & Generative Organs |first=William |last=Acton |authorlink=William Acton (doctor)|edition=third |year=1860 |publisher=John Churchill |location=London}}</ref>

While the number of users employing these non-standard plural forms of ''virus'' was always a small percentage of the English-speaking population, the variation was notable because it coincided with the growth of the [[World Wide Web|web]], a medium on which users of ''viri'' were over-represented. As the distribution of Internet users shifted to be more representative of the population as a whole during the 2000s, the non-standard forms saw decline in usage. A tendency towards prescriptivism in the computer enthusiast community, combined with the growing awareness that ''viri'' and ''virii'' are not etymologically supported plural forms, also played a part.{{Citation needed|date=March 2012}}

''Vīrus'' in [[Classical Latin]] was a [[mass noun]], denoting something uncountable. These pluralize only under special circumstances, and no plural form of the word can be found in contemporary texts.<ref>June 1999 issue of ASM News by the American Society for Microbiology</ref>

The Latin word ''vīrus'' was a neuter noun of the second [[Latin declension|declension]], but neuter second declension nouns ending in ''-us'' (rather than ''-um'') are rare enough that inferring rules is difficult. (One rare attested plural, ''pelage'' as a plural of ''pelagus'', is borrowed from Greek, so does not give guidance for ''virus''.) Plural neuter nouns of other declensions always end in ''-a'' (in the nominative, accusative and vocative).

In [[Neo-Latin]], a plural form is necessary in order to express the modern concept of 'viruses', leading to the following declension:<ref>[http://www.interrete.de/latein/nuntiifinarch1.html Nuntii Latini: Finnish Broadcasting Company (Radiophonia Finnica Generalis). Archiv I. 19.5.2000 - 6.12.2002]: "NOVUM VIRUS COMPUTATORIUM<br />Novum viri computatorii genus nomine Code Red in praesenti in Interreti grassatur, ut nuntiavit institutum SANS, cuius est securitati retis informatici providere. Code Red II, quod per cursum electronicum diffunditur, priore viro acerbius est et, postquam in servitoria penetravit, in systema lacunam facit. Ita fieri potest, ut alia vira eaque etiam periculosiora in machinas computatorias irrepant. Iam vermis Code Red I molestissimus fuit, cum biduo in trecenta milia computatrorum in omni orbe terrarum invasit."</ref><ref>[http://de.pons.com/%C3%BCbersetzung?l=dela&q=virus Pons: ''virus'']</ref><ref>William T. Stearn: ''Botanical Latin. History, Grammar, Syntax, Terminology and Vocabulary.'' David & Charles, third edition, 1983. Quote: "Virus: virus (s.n. II), ''gen. sing.'' viri, ''nom. pl.'' vira, ''gen. pl.'' vīrorum (to be distinguished from ''virorum'', of men)."</ref>

{| class="wikitable" border="1"
|-
!  !! singular !! plural
|-
| nominative<br />[[vocative]]<br />[[accusative]] || ''vīrus'' || ''vīra''
|-
| [[genitive]] || ''vīrī''<br />(antique, [[Proto-Indo-European nominals#Heteroclitic stems|heteroclitic]]: ''vīrus'')  || ''vīrōrum''
|-
| [[dative]]<br />[[ablative]] || ''vīrō''  || ''vīrīs''
|}

Usage of ''virii'' within Internet communities has met with some resistance, most notably by Tom Christiansen, a figure in the [[Perl]] community, who researched the issue and wrote what eventually became referred to in various online discussions as the authoritative essay on the subject,<ref name = "Christiansen">{{cite web|accessdate=29 December 2010|date=17 December 1999|author=Tom Christiansen|authorlink=|url=http://www.ofb.net/~jlm/virus.html|title=What's the Plural of 'Virus'?|publisher=Rick Moen}}</ref> favoring ''viruses'' instead of ''virii''. The impetus of this discussion was the potential irony that the use of ''virii'' could be construed as a claim of superior knowledge of language when in fact more detailed research finds the native ''viruses'' is actually more appropriate. In other words, ''virii'' is a [[hypercorrection]].

The form ''viruses'' appears in the official Scrabble words list,<ref>''OSW Official Scrabble Words'' (1989) Chambers</ref> but neither ''viri'' nor ''virii'' does.

In life sciences, "viruses" generally refers to several distinct strains or species of virus. "Virus" is used in the original way as an uncountable mass noun, e.g. "a vial of virus". Individual, physical particles are called "[[virion]]s" or "virus particles".

==''Octopus''==
There are three plural forms of ''[[octopus]]'': ''[[wikt:octopuses|octopuses]]'', ''[[wikt:octopi|octopi]]'', and ''[[wikt:octopodes|octopodes]]''. A fourth form ''octopods''  is occasionally used by scientists for taxonomic purposes.<ref>[https://www.ncbi.nlm.nih.gov/pubmed/?term=octopods PubMed search for octopods]. Retrieved March 18, 2018</ref>

Currently, ''octopuses'' is the most common form in the UK as well as the US; ''octopodes'' is rare, and ''octopi'' is often objected to as incorrect.<ref>Peters, Pam (2004). ''The Cambridge Guide to English Usage''. Cambridge: Cambridge University Press. {{ISBN|0-521-62181-X}}, p. 388.</ref>

The ''[[Oxford English Dictionary]]''<ref>[https://www.oed.com/dictionary/octopus_n?tab=forms#33758176 Oxford English Dictionary] Retrieved November 2, 2023.</ref> lists ''octopi'', ''octopuses'' and ''octopodes'' (in that order); it labels ''octopodes'' "rare", and notes that ''octopi'' derives from the mistaken assumption that ''{{lang|la|octōpūs}}'' is a [[Latin declension#d2|second declension Latin noun]]. (The long "ū" is not used in the 2nd declension.) Rather, it is (Latinized) [[Ancient Greek]], from ''{{Transliteration|grc|oktṓpous}}'' ({{lang|grc|ὀκτώπους}}, gender masculine), whose plural is ''{{Transliteration|grc|oktṓpodes}}'' ({{lang|grc|ὀκτώποδες}}).

''Chambers 21st Century Dictionary''<ref>[http://www.chambersharrap.co.uk/chambers/features/chref/chref.py/main?title=21st&query=octopus Chambers 21st Century Dictionary]. Retrieved October 19, 2007.</ref> and the ''Compact Oxford Dictionary''<ref>[https://web.archive.org/web/20080808223533/http://www.askoxford.com/concise_oed/octopus Compact Oxford Dictionary] Retrieved October 19, 2007.</ref> list only ''octopuses'', although the latter notes that ''octopodes'' is "still occasionally used"; the [[British National Corpus]] has 29 instances of ''octopuses'', 11 of ''octopi'' and 4 of ''octopodes''.{{citation needed|date=August 2023}}  ''Merriam-Webster 11th [[Merriam-Webster Collegiate Dictionary|Collegiate Dictionary]]'' lists ''octopuses'' and ''octopi'' (in that order);{{citation needed|date=August 2023}} ''[[Webster's New World College Dictionary]]'' lists ''octopuses'', ''octopi'' and ''octopodes'' (in that order).{{citation needed|date=August 2023}}

''[[Fowler's Modern English Usage]]'' states that "the only acceptable plural in English is ''octopuses,''" and that ''octopi'' is misconceived and ''octopodes'' [[pedantic]].<ref>Burchfield, R.W., ''Fowler's Modern English Usage,'' Oxford University Press, 539.</ref>

The term ''octopod'' (plural ''octopods'') is taken from the [[taxonomic order]] Octopoda but has no classical equivalent. The collective form ''octopus'' is usually reserved for animals consumed as food.

== ''Platypus'' ==
The situation with the word ''[[platypus]]'' is similar to that of ''octopus''; the word is etymologically Greek despite its Latinized ending, and so pluralizing it as if it were Latin (i.e. as ''platypi'') is sometimes ill-considered. As with ''octopus'', importing Greek morphology into English would have ''platypodes'' as the plural, but in practice this form is hardly attested outside of discussions about pluralization. In scientific contexts, biologists often use ''platypus'' as both the singular and plural form of the word, in the tradition of ''sheep'' or ''fish'', but laypersons and scientists alike often use the simple English plural ''platypuses''. Different dictionaries make different recommendations.

==Botanical Latin==
As a word in [[Botanical Latin]] (as distinct from Classical Latin), ''[[cactus]]'' follows standard Latin rules for pluralization and becomes ''cacti'', which has become the prevalent usage in English.  Regardless, ''cactus'' is popularly used as both singular and plural, and is cited as both singular and plural.<ref>''Random House Unabridged Dictionary'' (2006)</ref> ''Cactuses'' is also an acceptable plural in English.

==Facetious formations==
{{See also|Dog Latin}}
Facetious mock-erudite plurals in ''-i'' or even ''-ii'' are sometimes found for words ending with a sound (vaguely) similar to ''-us''. Examples are ''stewardi'' (supposed plural of ''[[Flight Attendant|stewardess]]'') and ''Elvi'' (as a plural for ''[[Elvis Presley|Elvis]]'' imitators). The Toyota corporation has determined that their ''Prius'' model should have the plural form ''Prii'', even though the Latin word ''prius'' has a plural ''priora'', the ''[[Lada Priora]]'' having prior claim to that name—though the common plural is "Priuses".<ref>engadget, [https://www.engadget.com/2011/02/21/toyota-decrees-the-plural-of-prius-is-prii-your-latin-teach/ "Toyota decrees the plural of 'Prius' is 'Prii,' your Latin teacher looks on admonishingly"],  Tim Stevens, 21 February 2011</ref><ref>[http://automotive.speedtv.com/article/green-toyota-readies-fleets-of-priuses/ "GREEN: Toyota Readies Fleet Of Priuses"], John Voelcker</ref> Conversely, Toyota has also said that the plural of their ''Lexus'' line is ''Lexus''.<ref>jalopnik, [https://jalopnik.com/breaking-minds-and-spirits-everywhere-lexus-says-the-p-1834330863 Breaking Minds and Spirits Everywhere, Lexus Says the Plural of 'Lexus' Is 'Lexus'], Alanis King, 26 April 2019</ref>   The [[Winklevoss twins]] were famously referred to as "the Winklevi" in [[The Social Network|''The'' ''Social Network'']].<ref>Vanity Fair, [http://www.vanityfair.com/business/features/2011/12/winklevosses-201112 "The Code of the Winklevi"], Dana Vachon, December 2011</ref>

==References==
{{Reflist}}
*{{cite web | accessdate=2 January 2005|url=http://dictionary.reference.com/help/faq/language/g63.html|title=What is the plural of virus?|work=reference.com FAQ }}

{{DEFAULTSORT:Plural Form Of Words Ending In -Us}}
[[Category:English grammar]]