Instances are the actual objects built in accordance with the qualities of the class.

 

A set of objects and the operations on those objects.

 

Encapsulation means that names (of variables and methods) are stored in locations that then have to be accessed, called namespaces.

 

Data hiding makes data invisible to users of the object, requiring it to be accessed only via the object's methods.

 

Subclasses can use all the functions of their superclass. They can also use any functions that are defined within the subclass; however, if the subclass uses the same name for a function which has also been used in the superclass, it will only use the subclass definition of that function.