A MonkeyPatch is a piece of Python code which extends or modifies other code at runtime (typically at startup). MonkeyPatching would be the practice of writing, or running, a monkeypatch.
A simple example looks like this:
from SomeOtherProduct.SomeModule import SomeClass def speak(self): return "ook ook eee eee eee!" SomeClass.speak = speak
In this example, if SomeClass did not already have a speak() method, it does now :-) If it had a speak() method before, the new code has replaced the old method definition.