Communication is a process of transferring information from one entity to another.
Communication is commonly defined as "the imparting or interchange of thoughts, opinions, or information by speech, writing, or signs".
Communication can be perceived as a two-way process in which there is an exchange and progression of thoughts, feelings or ideas towards a mutually accepted goal or direction.
Animal communication is any behaviour on the part of one animal that has an effect on the current or future behavior of another animal. Of course, human communication can be subsumed as a highly developed form of animal communication.
Communication, as an academic discipline, has a long history.
(excerpts from http://en.wikipedia.org/wiki/Communication)