Disciplinarity, multidisciplinary, interdisciplinarity and transdicliplinarity are like four arrows shot from but a single bow: knowledge.
Nicolescu disinquishes transdisciplinarity from the other arrows as “that which is at once between the disciplines, across the disciplines, and beyond all discipline. It’s goal is the understanding of the present world…” Nicolescu, 1998
http://perso.club-internet.fr/nicol/ciret/bulletin/b12/b12c8.htm