(1) A message fragment containing Data or information. When messages are sent on the Internet, they are broken into smaller, more easily transportable pieces called packets. Each packet consists of a Header and a piece of the message. A single e-mail message may actually be broken into a half-dozen different packets. (2) A technique used to break large quantities of data into small groups, or packets, to facilitate Transmission with very few errors. (3) A single group of digital signals sent from an originator to an addressee.