Chatter may refer to: Chatter (machining) or machining vibrations the undesirable phenomenon of oscillations having finite frequency and amplitude, in sliding mode control Contact bounce or chatter, a common problem with mechanical switches and relays Chatter (signals intelligence), the volume of communication to or from suspected terrorists or spies Project CHATTER (1947–53), a U.S. Navy truth serum project Chatter (software), enterprise social networking software Small talk See also Chat (disambiguation) Chattering classes, a politically active, socially concerned and highly educated section of the "metropolitan middle class" Chatter mark, an indication of glacial erosion Chatter Telephone, a classic roll along pull toy with a friendly face and eyes that move up and down when the toy is pulled.