You did not hear about observer, but you probably heard about publisher/subscriber (most gui frameworks use this, even wxPython with pubsub).

Adapter is a generic name. Compatibility modules that enable python code to run with python 2 and python 3 are adapters. For example: https://github.com/bartdag/py4j/blob/master/py4j-python/src/...

As for the visitor pattern: http://docs.python.org/library/compiler.html#module-compiler...