Communication (from Latin "communis", meaning to share) is the activity of conveying information through the exchange of thoughts, messages, or information, as by speech, visuals, signals, writing, or behavior.
Communication requires a sender, a message, and a recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast distances in time and space. Communication requires that the communicating parties share an area of communicative commonality. The communication process is complete once the receiver has understood the message of the sender.
Read more about Communication: Human Communication, Nonhuman Communication, Communication Cycle, Communication Noise