See the code below
class HelloWorld:
def print(self):
print "Hello World"
Is HelloWorld.print(self) called a method or a function in Python?
They are referred to as class methods or instance methods.
Just to add to Jakob's clear answer, in languages like Python there is no requirement that everything lives within a class, unlike (say) Java. So whereas in Java every function is a method, in Python this isn't true: many or even most functions aren't part of a class. That's why it makes sense to have this terminology distinction between methods and functions.