Interdisciplinarity involves attacking a subject from various angles and methods, eventually cutting across disciplines and forming a new method for felicitious understanding of the subject.
Multidisciplinary examines multiple subjects from different disciplines but only uses the methods of one discipline in its examination.
A transdisciplinary approach dissolves boundaries between disciplines.
Crossdisciplinarity describes a method that crosses disciplinary boundaries but does so from a foreign angle and with no cooperation.
Non-disciplinarity is a conscious and deliberate rather than ignorant disregard of the expectation that one should remain within the subject matter and methodology of a defined discipline.
(source: http://en.wikipedia.org/wiki/Interdisciplinary#Varieties_of_disciplinarity)
