Singular nouns represent one. Plural nouns represent two or more. The plural form of most nouns can be created by adding -s or -es to the end of the word. There are other plural nouns whose ending changes. In many cases there's a rule that can be followed. As grammar rules tend to go, there are exceptions, which are noted.
Regular Plural Nouns (based on word endings)
Irregular Plural Nouns
Irregular plural nouns are irregular because in some cases, the spelling changes to reflect the plural form and in other cases, the word reflects both the singular and plural form with no spelling changes.