These terms are organized hierarchically. The topmost tier includes a broad division of disciplines. The second and third tiers break these broad disciplines into more specific disciplines.
The broad-group terms should only be assigned when a finer-level term is not applicable. When finer-level terms are applied, the broad-group term is assumed as well.
Business - http://en.wikipedia.org/wiki/Business
Energy - http://en.wikipedia.org/wiki/Energy_development
Engineering - http://en.wikipedia.org/wiki/Engineering
Fine Arts - http://en.wikipedia.org/wiki/Fine_Arts
Health and Medicine - http://en.wikipedia.org/wiki/Health_profession
Humanities - http://en.wikipedia.org/wiki/Humanities
Mathematics - http://en.wikipedia.org/wiki/Mathematics
Science - http://en.wikipedia.org/wiki/Science
Social Science - http://en.wikipedia.org/wiki/Social_Science
Society - http://en.wikipedia.org/wiki/Society
Teaching and Education - http://en.wikipedia.org/wiki/Education