English noun/Catalogs/English irregular nouns

The normal way to form a plural noun in English is to add -s or, after s, z, ch and sh, -es. Words ending in -ŷ replace it with -íes. But there are also many irregular nouns, some with English roots, others with plural forms from Latin, Greek, French, Italian and Hebrew. (The accents, which are not part of the language, are included to show stress and pronunciation: see English spellings for a table and English phonemes for the IPA. Words in italics suggest meaning, and an equals sign is placed between homophones.)

Nouns in -o which always have -ôes in the plural are included in the table below; others are regular, having -ôs, while búffalo, càrgo, hâlo, mosquìto (-skì-), mótto, nô, tornâdo, volcâno and zêro can be seen with both -ôs and -ôes. Nouns in -us which always have -î in the plural are listed below, while cáctus, fôcus, fúngus, hippopótamus, óctopus and sýllabus can have both -î and -uses. Nouns in -sís (-ssíss), análysis, áxis, bâsis, crîsis, diagnôsis, émphasis, hypóthesis, neurôsis, oâsis, parénthesis, synópsis, sýnthesis and thêsis have their plurals in -sês (-ssêez): análysês (*ənáləssêez) etc.

Nouns in -ndum, addéndum, referéndum and memorándum, change to -nda: addénda, referénda, memoránda. Apart from vŏrtex, plural vŏrtices (-tíssêez), nouns in -ex and -íx (âpex, appéndix, cërvix, índex and mâtrix) have plurals in both -icês and -xes (-xíz). The following have the same form in the singular and plural: bárracks, cód, cróssroads, dêer animal (= dêar loved, expensive), dîce, físh (dîe as the singular of dîce and físhes as the plural of físh are archaic), gállows, hálibut, héadquarters, mêans, óffspring, përch fish (përch position has përches), pîke, sálmon (*sámmon), sêries, shêep, spêcies (-shíz), tròut and tûna. In the table, prefixed nouns are not included if their plural endings are the same as that of the root noun: for example the plural of snôwmán is snôwmén.

Table of irregular nouns
{|class="wikitable" width=60% style="margin-left: 2em;" !Singular !Plural {| class="collapsible collapsed" width=60% style="margin-left: 2em;" ! colspan=3 bgcolor="#dddddd" align=center|Comprehensive list
 * width=50%|'''bactêrium
 * width=50%|'''bactêria
 * '''chîld
 * '''chíldren
 * '''goôse
 * '''gêese
 * '''lôaf
 * '''lôaves
 * '''nûclêus
 * '''nûclêî
 * '''phenómenon
 * '''phenómena
 * '''vŏrtex
 * vŏrticês (-íssêez)
 * '''nûclêî
 * '''phenómenon
 * '''phenómena
 * '''vŏrtex
 * vŏrticês (-íssêez)
 * '''vŏrtex
 * vŏrticês (-íssêez)