Editing English plurals (section)

======Anglicisation======
The general trend with [[loanwords]] is toward what is called ''Anglicisation'' or ''naturalisation'', that is, the re-formation of the word and its inflections as normal English words. Many nouns have settled on, or acquired a modern form from the original (usually Latin). Other nouns have become Anglicised, taking on the normal "s" ending. In some cases, both forms are still competing.

The choice of a form can often depend on context: for a scholar, the plural of ''[[wikt:appendix|appendix]]'' is ''appendices'' (following the original language); for some physicians, the plural of ''appendix'' is ''appendixes''. Likewise, a [[radio]] or [[radar]] [[engineer]] works with ''antennas'', but an [[entomologist]] deals with ''antennae''. The choice of form can also depend on the level of discourse: traditional Latin plurals are found more often in academic and scientific contexts, whereas in daily speech the Anglicised forms are more common. In the following table, the Latin plurals are listed, together with the Anglicised forms when these are more common.

Different paradigms of Latin pronunciation can lead to confusion as to the number or gender of the noun in question. As traditionally used in English, including scientific, medical, and legal contexts, Latin nouns retain the classical inflection with regard to spelling; however, those inflections use an [[Traditional English pronunciation of Latin|Anglicised pronunciation]]: the entomologist pronounces ''antennae'' as {{IPA|/ænˈtɛni/}}. This may cause confusion for those familiar with the Classical Latin pronunciation {{IPA|/ænˈtɛnaɪ/}}. The words ''alumni'' (masculine plural) and ''alumnae'' (feminine plural) are notorious in this regard, as ''alumni'' in Anglicised pronunciation sounds the same as ''alumnae'' in [[Latin spelling and pronunciation#Ecclesiastical pronunciation|Classical Latin pronunciation]], and [[vice versa]].

Because many of these plurals do not end in ''-s'', some of them have been reinterpreted as singular forms: particularly the words ''datum'' and ''medium'' (as in a "medium of communication"), where the original plurals ''data'' and ''media'' are now, in many contexts, used by some as singular mass nouns: "The media is biased"; "This data shows us that&nbsp;..." (although a number of scientists, especially of British origin, still say "These data show us that&nbsp;..."). See [[#datum data|below]] for more information. Similarly, words such as ''criteria'' and ''phenomena'' are used as singular by some speakers, although this is still considered incorrect in standard usage (see [[#phenomenon|below]]).

Final ''-a'' becomes ''-ae'' (also ''-æ''{{citation needed|date=August 2017}}), or just adds ''-s'':
{{block indent|{{wikitable
|alumna||alumnae
|-
|antenna||antennae
|-
|aurora||aurorae/auroras
|-
|formula||formulae/formulas
|-
|encyclopaedia (or encyclopædia) / encyclopedia||| encyclopaedias / encyclopedias (encyclopaediae and encyclopediae are rare)
|-
|larva||larvae
|-
|pupa||pupae/pupas
}}}}
Scientific abbreviations for words of Latin origin ending in ''-a'', such as ''SN'' for ''supernova'', can form a plural by adding ''-e'', as ''SNe'' for ''supernovae''.

Final ''-ex'' or ''-ix'' becomes ''-ices'' (pronounced {{IPA|/ᵻsiːz/}}), or just adds ''-es'':
{{block indent|{{wikitable
|index||indices||{{IPA|/ˈɪndᵻsiːz/}}|| or indexes
|-
|matrix||matrices||{{IPA|/ˈmeɪtrᵻsiːz/}}
|-
|vertex||vertices||{{IPA|/ˈvɜːrtᵻsiːz/}}
}}}}

Final ''-is'' becomes ''-es'' (pronounced {{IPA|/iːz/}}) or ''-ises/-ides'':
{{block indent|{{wikitable
|axis||axes||{{IPA|/ˈæksiːz/}}
|-
|genesis||geneses||{{IPA|/dʒɛn.ə.siːz/}}
|-
|nemesis||nemeses||{{IPA|/ˈnɛməsiːz/}}
|-
|crisis||crises||{{IPA|/ˈkraɪsiːz/}}
|-
|testis||testes||{{IPA|/ˈtɛstiːz/}}
|-
|thesis||theses||{{IPA|/ˈθiːsiːz/}}
|-
|parenthesis||parentheses||{{IPA|/pəˈrɛnθəsiːz/}}
|-
|clitoris||clitorises/clitorides||{{IPA|/ˈklɪtərɪsiz/}}
}}}}
Except for words derived from Greek {{Lang|grc-Latn|polis}}, which become {{Lang|grc-Latn|poleis}} (pronounced {{IPA|/iːs/}} or {{IPA|/iːz/}}):
{{block indent|{{wikitable
|acropolis||acropoleis||{{IPA|/æˈkropoliːs/}}
}}}}

(Some of these are Greek rather than Latin words, but the method of plural formation in English is the same.) Some people treat ''process'' as if it belonged to this class, pronouncing ''processes'' {{IPA|/ˈprɒsᵻsiːz/}} instead of standard {{IPA|/ˈprɒsɛsᵻz/}}. Since the word comes from Latin {{Lang|la|processus}}, whose plural in the [[Latin declension#Fourth declension (u)|fourth declension]] is {{Lang|la|processūs}} with a long ''u'', this pronunciation is by [[Analogy#Linguistics|analogy]], not etymology. ''Axes'' {{IPA|(/ˈæksiːz/)}}, the plural of ''axis'', is pronounced differently from ''axes'' {{IPA|(/ˈæksᵻz/)}}, the plural of ''ax(e)''.

Final ''-ies'' remains unchanged:
{{block indent|{{wikitable
|series||series
|-
|species||species
}}}}
''Specie'' for a singular of ''species'' is considered nonstandard. It is standard meaning the form of money, where it derives from the Latin singular ablative in the phrase ''in specie''.

{{Anchor|datum_data}}Final ''-um'' becomes ''-a'', or just adds ''-s'':
{{block indent|{{wikitable|style="vertical-align:top"
|-
|addendum||addenda/addendums
|-
|agendum (obsolete, not listed in most dictionaries)||agenda means a "list of items of business at a meeting" and has the plural ''agendas''.
|-
|corrigendum||corrigenda
|-
|curriculum||curricula/curriculums
|-
|datum||data (now usually treated as a singular mass noun in both informal and educated usage, but usage in scientific publications shows a strong American/British divide; American usage generally prefers to treat ''data'' as a singular in all contexts, including in serious and academic publishing.<ref>"Sometimes scientists think of data as plural, as in ''These data do not support the conclusions.'' But more often scientists and researchers think of data as a '''''singular mass entity like information''''', and most people now follow this in general usage."<!-- Emphasis added or in original? --> {{cite web |url=http://www.bartleby.com/61/51/D0035100.html |title=Data. The American Heritage® Dictionary of the English Language: Fourth Edition. 2000. |access-date=2007-10-20 |url-status=dead |archive-url=https://web.archive.org/web/20071104104416/http://www.bartleby.com/61/51/D0035100.html |archive-date=4 November 2007}}</ref><ref>{{cite news |last1=O'Neill |first1=Dan |title=Data is/data are |department=Community Science Forum |url=https://newspaperarchive.com/fairbanks-daily-news-miner-sep-22-1979-p-22/ |url-access=subscription |work=Fairbanks Daily News-Miner |volume=77 |issue=224 |date=September 22, 1979 |page=B-2 |via=[[Newspaper Archive]] |quote=[O]f the 136 distinguished consultants on usage polled for the 1975 Harper Dictionary of Contemporary Usage, 49 per cent responded that they use 'The data is...' in writing. And, in casual speech, 65 per cent use data as singular. Those who defend 'The data is...' often point to the fact that agenda is also, strictly, a plural, but is nearly always regarded as a single list and takes a singular verb. You'll probably never hear anyone ask: 'Are the agenda interesting?'}}</ref><ref>{{cite web|url=http://www.iq.harvard.edu/blog/sss/archives/2007/09/how_many_data_a.shtml|title=Summary of dictionary sources and scholarly usage|website=Harvard University|access-date=6 April 2018|archive-url=https://web.archive.org/web/20080515213104/http://www.iq.harvard.edu/blog/sss/archives/2007/09/how_many_data_a.shtml|archive-date=15 May 2008|url-status=dead}}</ref> British usage now widely accepts treating ''data'' as singular in standard English,<ref>''New Oxford Dictionary of English'', 1999</ref> including educated everyday usage<ref>"...&nbsp;in educated everyday usage as represented by the ''Guardian'' newspaper, it is nowadays most often used as a singular." {{cite web|url=http://www.eisu2.bham.ac.uk/johnstf/revis006.htm |author=Tim Johns |title=Data: singular or plural? |website=Tim Johns EAP Page |access-date=2014-06-27 |url-status=dead |archive-url=https://web.archive.org/web/20090211165815/http://eisu2.bham.ac.uk/johnstf/revis006.htm |archive-date=11 February 2009 }}</ref> at least in non-scientific use.<ref>{{cite web|url=https://www.oxforddictionaries.com/|archive-url=https://web.archive.org/web/20010516042450/http://www.oxforddictionaries.com/|url-status=dead|archive-date=16 May 2001|title=Oxford Dictionaries |website=Oxford Dictionaries|access-date=6 April 2018}}</ref>{{nonspecific|date=June 2022}} British scientific publishing usually still prefers treating ''data'' as a plural.<ref>{{cite web|url=http://www.eisu2.bham.ac.uk/johnstf/revis006.htm |author=Tim Johns |title=Data: singular or plural? |website=Tim Johns EAP Page |access-date=2014-06-27 |url-status=dead |archive-url=https://web.archive.org/web/20090211165815/http://eisu2.bham.ac.uk/johnstf/revis006.htm |archive-date=11 February 2009 }}</ref> Some British university style guides recommend using ''data'' for both the singular and the plural use<ref>[http://www.nottingham.ac.uk/public-affairs/uon-style-book/singular-plural.htm UoN "Style Book – Singular or plural"]. Media and Public Relations Office, University of Nottingham. {{webarchive |url=https://web.archive.org/web/20100726063013/http://www.nottingham.ac.uk/public-affairs/uon-style-book/singular-plural.htm |date=26 July 2010 }}</ref> and some recommend treating it only as a singular in connection with computers.<ref>{{cite web|url=http://openlearn.open.ac.uk/mod/resource/view.php?id=182902|title=Open Learning |publisher=Open University|access-date=6 April 2018}}</ref>)

In engineering, drafting, surveying, and geodesy, and in [[weight and balance#Terms|weight and balance]] calculations for aircraft, a [[datum (geodesy)|datum]] (plural datums or data) is a reference point, surface, or axis on an object or the Earth's surface against which measurements are made.
|-
|forum||fora/forums (''fora'' is rare and might only be used to refer to more than one original Roman forum)
|-
|medium||media (in [[communication system]]s and [[digital computer]]s; this is now often treated as a singular mass noun); mediums (spiritualists, or items of medium size)
|-
|memorandum||memoranda/memorandums
|-
|millennium||millennia/millenniums
|-
|ovum||ova
|-
|referendum||referendums (often taken to mean plebiscites, and referenda as the propositions voted on. It is often argued that ''referenda'' is incorrect because it is a Latin [[gerund]], which did not have a plural form, while the "propositions voted on" is more like a [[gerundive]], which could be pluralised.)
|-
|spectrum||spectra (as in [[power spectrum]] in [[electrical engineering]])
|-
|stadium||stadia/stadiums (the latter is far more common)
|-
|stratum||strata
}}}}

{{Anchor|plural_for_suffix_us}}Final ''-us'' becomes ''-i'' ([[second declension]], {{IPA|[aɪ]}}) or ''-era'' or ''-ora'' ([[third declension]]), or just adds ''-es'' (especially for [[fourth declension]] words, where the Latin plural was similar to the singular):
{{block indent|{{wikitable|style="vertical-align:top"
|alumnus||alumni
|-
|cactus||cactuses/cacti (in [[Arizona]] many people avoid either choice with ''cactus'' as both singular and plural){{Citation needed|date=February 2021}}
|-
|campus||campuses (The Latinate plural form ''campi'' is sometimes used, particularly with respect to colleges or universities; however, it is sometimes frowned upon. By contrast, the common plural form ''campuses'' is universally accepted.){{Citation needed|date=February 2021}}
|-
|corpus||corpora/corpuses
|-
|census||censuses
|-
|focus||foci/focuses
|-
|fungus||fungi
|-
|genus||genera
|-
|hippopotamus||hippopotamuses/hippopotami
|-
|octopus||octopuses (''octopi'' also occurs, although it is strictly speaking unfounded<ref>{{cite web|url=http://www.oxforddictionaries.com/us/words/what-are-the-plurals-of-octopus-hippopotamus-syllabus|archive-url=https://web.archive.org/web/20131101044550/http://www.oxforddictionaries.com/us/words/what-are-the-plurals-of-octopus-hippopotamus-syllabus|url-status=dead|archive-date=1 November 2013|title=What are the plurals of 'octopus', 'h... - Oxford Dictionaries|website=Oxford Dictionaries - English|access-date=6 April 2018}}</ref> because it is not a Latin noun of the second declension, but rather a Latinized form of Greek {{Lang|grc|ὀκτώπους|size=90%}} [{{Lang|grc-Latn|oktṓpous}}, "eight-foot"]. The theoretically correct form ''octopodes'' is rarely used.)
|-
|platypus||platypuses (same as ''octopus'': ''platypi'' occurs but is etymologically incorrect, and ''platypodes'', while technically correct, is even rarer than ''octopodes'')
|-
|prospectus||prospectuses (plural ''prospectus'' is rare although correct in Latin)
|-
|radius||radii
|-
|succubus||succubi (the word ''omnibus'' is similar in form but is originally dative plural, so cannot be pluralised to *''omnibi'': see ''[[The Motor Bus]]'')
|-
|stylus||styli/styluses
|-
|syllabus||syllabi/syllabuses
|-
|terminus||termini/terminuses
|-
|uterus||uteri/uteruses
|-
|viscus||viscera
|-
|virus||viruses (see {{format link|Plural form of words ending in -us#Virus}})
}}}}

Final ''-us'' remains unchanged in the plural (fourth declension—the plural has a long ū to differentiate it from the singular short u):
{{block indent|{{wikitable|style="vertical-align:top"
|meatus||meatus (but usually ''meatuses'')
|-
|status||status (but usually ''statuses'')
|-
|apparatus||apparatus (but usually ''apparatuses'')
}}}}

Colloquial usages based in a humorous fashion on the second declension include ''Elvii'' (better Latin would be ''Elvēs'' or Elvidēs) to refer to multiple [[Elvis impersonators]], and ''Loti'', used by [[wikt:petrolhead|petrolheads]] to refer to [[Lotus Cars|Lotus]] automobiles in the plural.

Some Greek plurals are preserved in English (''cf.'' [[English words of Greek origin#Inflectional endings and plurals|Plurals of words of Greek origin]]):

{{Anchor|phenomenon}}Final ''-on'' becomes ''-a'':
{{block indent|{{wikitable
|automaton||automata/automatons
|-
|criterion||criteria/criterions (the latter form is rare)
|-
|phenomenon||phenomena/phenomenons (the latter form is common, though sometimes proscribed)
|-
|polyhedron||polyhedra/polyhedrons
}}}}

Final ''-as'' in one case changes to ''-antes'':
{{block indent|{{wikitable
|Atlas||Atlantes (statues of the Titan); but
|-
|atlas||atlases (map collections)
}}}}

Final ''-ma'' in nouns of Greek origin can become ''-mata'', although ''-s'' is usually also acceptable, and in many cases more common.
{{block indent|{{wikitable
|stigma||stigmata/stigmas
|-
|stoma||stomata/stomas
|-
|schema||schemata/schemas
|-
|dogma||dogmata/dogmas
|-
|lemma||lemmata/lemmas
|-
|magma||magmata/magmas
|-
|anathema||anathemata/anathemas
|-
|enema
|enemata/enemas
}}}}
Such ''-ata'' plurals also occur in Latin words borrowed from Greek, e.g. ''poemata''. The ''a'' is short in both languages.