What is a class?

One day on my class, I asked a question to students, What is a class? Everyone came up with a definition. One popular definition was "A class is a group of objects". I stunned at this answer. This was a definition stated in text book.
I started to explain the definition, "A class is s group of objects". I showed them a pen and told them that the pen is an object. All agreed. Then I showed three pens, so a group of pen, a group of objects.
If so, then the three pens should be called as a class.

Huh..

It is not. It is absolutely wrong understanding....

Then what is a class..

A class is simply a representation of a type of object. It is the blueprint/ plan/ template that describe the details of an object. A class is the blueprint from which the individual objects are created. Class is composed of three things: a name, attributes, and operations.

I need to explain this further.

For example, take any object say a table. It has so many characteristics. Let me specify some of those.

1. Color of the table.
2. Size of the table.
3. Price
4. No. of Legs.

 These are the properties or attributes of a table.
So we can form a class like the following

Class Table{

• Color
• Size
• Price
• NoOfLegs

}