`meth` is just a historical abbreviation.

Mind that support for methods as first-class objects was introduced with Python 2.5 [0].

That was in 2006, a few years before "meth" became engrained in European popular culture as an abbreviation for methamphetamines. The abbreviation was never changed.

[0]: https://docs.python.org/release/2.5/lib/typesmethods.html