class: A class is a set of attribute and method definitions performing certain specific functionality. Classes can inherit methods and attributes from one or more parent classes. Classes do not contain actual values for attributes; they only describe them.

instance: An instance is a set of attribute values (as described by the class) and associated methods. Instances are also called objects. Instances are created from classes by "calling" the class, with arguments required by the constructor. For example, to create an instance of a class named "class" one would write class(arg1, arg2 [,.. argN]) where arg1 and arg2 are arguments of the constructor.

method: A function working in the context of an instance. It automatically receives a "self" argument which can be used to fetch or set attributes stored in the associated instance.

type: Variables in Python are not strongly typed, meaning that it is possible to assign any kind of values to a variable; typing is assigned to the value.

attribute: An attribute of an object is a variable holding some value, interpreted and manipulated by object methods. Although Python is not strongly typed, types were assigned to the variables in Zorp to indicate what kind of values they are supposed to hold.

actiontuple: A tuple is a simple Python type defined as a list of values. An actiontuple is a special tuple defined by Zorp where the first value must be a value specifying what action to take, and trailing items specify arguments to the action. For example (HTTP_REQ_REJECT, "We don't like this request") is a tuple for rejecting HTTP requests and returning the message specified in the second value.