A plural noun is a word that refers to that there is more than one person, animal, place, thing, or idea. To make a singular noun plural add 's', 'es', or 'ies' to the end.
There are a few exceptions to this rule, but not many.
1. A single moose is a moose, and a group of moose is still moose.
2. A single deer is a deer, and a group of deer are still deer
Click here to see more examples of irregular plural nouns.