Plural nouns of irregular nouns
Most singular nouns are made plural by simply putting an -s at the end. ... The correct spelling of plurals usually depends on what letter the singular noun ends in. To make regular nouns plural, add ‑s to the end. ... If the singular noun ends in ‑s, -ss, -sh, -ch, -x, or -z, add ‑es to the end to make it plural.
A plural noun indicates that there is more than one of that noun (while a singular noun indicates that there is just one of the noun). Most plural forms are created by simply adding an -s or –es to the end of the singular word. For example, there’s one dog (singular), but three dogs (plural). However, English has both regular and irregular plural nouns. Regular plurals follow this rule (and other similar rules), but irregular plurals are, well, not regular and don’t follow a “standard” rule.
