n. (of a class)
an object the class of which is either that class itself,
or some subclass of that class. (Because of the correspondence between
types and classes, the term "generalized instance of X"
implies "object of type X" and in cases where X is a class
(or class name) the reverse is also true.
The former terminology emphasizes the view of X as a class
while the latter emphasizes the view of X as a type specifier.)
n. a function whose behavior depends on the classes or
identities of the arguments supplied to it and whose parts include, among
other things, a set of methods, a lambda list, and a
method combination type.