A plural noun is a word that refers to more than one person, place, thing, or idea. Most plural nouns are formed by adding -s or -es to the singular form, such as "cat" becoming "cats" and "box" becoming "boxes"

​What is a plural?

Add an "s" to most of the nouns:
dog - dogs
bed-beds
mirror -mirrors
table -tables
window -windows.

Rule # 1

If the noun ends in "ch, sh, x, z, s, and C+ o" add "es":
watch - watches
dish -dishes
box-boxes.
tomato - tomatoes
dress -dresses
buzz- buzzes

Rule #2

​Only if the noun ends in Consonant + Y change it for "i" and add "es"

baby - babies
library - libraries
party - parties

Rule #3

​Change the "f" of "fe" for "ves"
knife- knives
wolf -wolves
wife- wives

** There are exceptions like: roof- roofs, chef-chefs, chief-chiefs

​​Rule #4

​There are some nouns that are the same in singular and plural:
deer-deer
sheep-sheep
fish -fish
bison-bison
candy-candy

​​Rule # 5

man -men
woman -women
child -children
person- people
foot- feet
tooth-teeth
goose -geese
cactus -cacti
confetto -confetti

​Irregular nouns (they completely change)