Wordnet 3.0
NOUN (1)
1. 
 a branch of knowledge; 
- Example: "in what discipline is his doctorate?"- Example: "teachers should be well trained in their subject"- Example: "anthropology is the study of human beings"[syn: discipline, subject, subject area, subject field, field, field of study, study, bailiwick]
WordNet (r) 3.0 (2006):
subject area
    n 1: a branch of knowledge; "in what discipline is his
         doctorate?"; "teachers should be well trained in their
         subject"; "anthropology is the study of human beings" [syn:
         discipline, subject, subject area, subject field,
         field, field of study, study, bailiwick]