An English noun exhibits a two-way distinction of number: a singular form, denoting one of something, and a plural form, denoting two or more. Here are the guidelines for creating plural nouns.
Add -s to form the plural of most nouns.
Add -es if the noun ends in -s, -sh, -ch, or -x.
If a noun ends in consonant + y, change the -y to -i and add -es.
If a noun ends in vowel + y, add -s. Words ending in -quy don’t follow this rule (as in soliloquies).
Add -s to most nouns ending in -f.
Exceptions: In some cases, change the -f to -v and add -es
In compound words, make the main word plural.