What does 'is an instance of' mean in Javascript?

Question

The answer to this question: What is the initial value of a JavaScript function's prototype property?

has this sentence:

The initial value

Answer 1

Javascript doesn't use classical inheritance, it uses prototypal inheritance where everything is an "Object" and inheritance is accomplished by cloning, for example:

var myPrototype = function() {
   var privateMember = "I am private";
   var publicMember = "I am public";
   var publicMethod = function () {
       alert(privateMember); 
   }
   return {
      publicMember = publicMember,
      publicMethod = publicMethod
   }
}

var myInstace = new myPrototype();
myInstance.publicMethod();

here myInstance can be said to be an "instance of" myPrototype, but in reality what happened is by using the new keyword you cloned myPrototype to create myInstance.