How would you explain a five year old kid what is a object data type ?

Answer 1

To explain to a 5-year-old, what is an Object.

Tell them that Objects in the programming language are like Objects in real life. Example, say the object...
function Lion() { this.init = function() {} }
... is the same thing as...
A Toy Lion on the child's shelf.

The Object's "ROAR" Method can be the Lion's Big Loud Roar.

In basic, to explain to a young child the fundsmentals of programming, you over-simplify - expanding upon their knowledge at a later date, when they have matured and understand what you are saying.

Answer 2

It is like a knife. Every knife are BASICALLY the same, they have a blade. But every knife have its own blade, some longer, some rusted, some with "teeth"