1) Bailiwick 2) Branch of knowledge 3) Communication theory 4) Discipline 5) Field 6) Field of study 7) Study 8) Subject 9) Subject area 10) Subject field 1) Comms 2) Connections 3) Messages 
[n] - the discipline that studies the principles of transmiting information and the methods by by which it is delivered (as print or radio or television etc.)
communications 1. The art and technique of using words effectively to impart information or ideas. 2. The field of study concerned with the transmission of information by various means; such as, with print or broadcasting or any of the various professions involved with the transmission of information; such as, advertising, broadcasting, or journal...
communication theory noun the discipline that studies the principles of transmiting information and the methods by which it is delivered (as print or radio or television etc.); `communications is his major field of study`