What is a Class in Object Oriented Programming (OOP)?

Definition:

Class is a declaration, a template, or a blueprint that can be used to classify objects.

For example, the peacock, the sparrow, and the kingfisher are all birds. All of them share characteristics that are common to the family of birds. All of them lay eggs, are covered with feathers, have hollow bone structures, and have the ability to fly. Therefore, they share structural and behavioral similarities and belong to the class called Birds.