Interdisciplinarity

Interdisciplinarity is when two or more subjects (academic disciplines) join up. This happens when a problem overlaps traditional academic boundaries. Other terms which mean almost the same thing are multidisciplinarity and crossdisciplinarity.
An examples makes clear what is meant:
Other examples include artificial intelligence, cultural studies, cybernetics, computational linguistics, biomedical engineering, and so on. Physical chemistry, biochemistry and astrophysics must have been some of the first.
In many universities, traditional departments (e.g. botany, zoology) were scrapped, and new broader departments like 'School of biological sciences' were formed. Inside this umbrella, research and teaching teams were based on interdisciplinary problems, such as ecology or cell division or Earth history. There are some necessary specialities which do not fit easily into the new system. Examples are taxonomy (you still need people to identify animals) and areas like parasitology and agricultural botany. 
A system which works in some universities is to appoint staff to the Schools (usually Humanities, Science. Social sciences and Technology) and let the staff join those groups which best fit their expertise.